Why did the popularity of Buddism in India decline significantly after the sixth century despite it being the birthplace of Buddism?

Mental you death meditationu death penaltyu dedication of meritu definitive meaningu degenerate ageu delusions of views and thoughtu dependent and main rewardsu dependent originationu devadattau devanampiya tissau dhammapada sutrau dhammapalau dharma door of emptinessu dharma door of existenceu dharma ending ageu dharma eyeu dharma masteru dharma natureu dharma princeu dharma realm treasury bodyu dharmakarau dharmakara’s vowsu dharmakayau dhyana heavensu dhyani buddhasu diamond recitationu diamond sutrau diamond vehicleu differentiating knowledgeu difficult path of practiceu dipamkara buddhau discipline methodu discouragementu discourse on the golden lionu discriminationu divine earu door of liberationu drum of the teachingu dry wisdomu dual birthu eagle peaku earth store bodhisattvau eastern buddhist, theu easy path of practiceu easy practice chapteru eating when hungryu eight abstinencesu eight adversitiesu eight attributes of nirvanau eight bodhisattvasu eight classes of divinitiessee: eight divisions (of divinities)syn: eight classes of divinitiesu eight impure thingsu eight liberationssee: eight samadhis of emancipationu eight preceptsu eight samadhis of emancipationu eight sufferingsu eight teachingsu eightfold liberationu eightfold noble pathu eighth consciousnessu eighty auspicious marksu eighty minor characteristicssee: eighty auspicious marksu eighty minor excellenciesu elixir of lifeu emei mountainu emptinessu empty eonu empty store bodhisattvau encyclopedia of buddhismu energy currentsu enlightenmentu entering the streamu equanimityu esoteric schoolu essentials of rebirthu eternalismu ethereal birthu euthanasiau everyday mind is the wayu everything is made from mindu evil pathsu evil planes of existenceu exclusion clauseu exclusive practiceu excommunicationu exhaustive meaningu expedient meansu expedientsu externalist viewsu extinctionu fads in buddhismu faith healingu false thinkingu festivalsu field of blessingsu fields of meritsu filialityu finger pointing at the moonu fish gongu five aggregatesu five cardinal sinsu five corruptionsu five defilementsu five depravitiesu five fearsu five good rootsu five grave offensesu five houses of chanu five impedimentsu five kinds of eyesu five marks of decayfive periods / eight teachingsu five preceptsu five schools of zenu five sensuous pleasuresu five skandhasu five turbiditiesu flower adornment sutrau flower and smileu flower bank mysterious gatesu flower garland scriptureu flower ornament sutrau flower store worldu flowers and fruitsu foreign dust afflictionsu foremost meaningu fortune tellingu four attractionsu four bases of miraculous powersu four constituentsu four continentsu four currentsu four dharma realmsu four elementsu four famous mountainsu four fearlessnessesu four forms of birthu four great debtsu four great oceansu four great vowsu four guardian kingssee: four heavenly kingsu four heavenly kingsu four holy truthsu four immeasureable mindsu four integrative methodsu four inverted viewsu four kinds of devoteesu four landsu four means of salvationu four meditationsu four mindfulnessesu four modes of birthu four noble truthsu four propositionsu four pure landsu four reliancesu four right effortsu four stages of arhatshipu four sufferingsu four virtues of nirvana you four wrong viewsu friends of the western buddhist orderu fruits and flowersu funerary rites for the buddhau gandavyuha sutrau gandharvau garden of anathapindikau generosityu golden lion treatiseu good destiniessee: good planes of existenceu good kalpau good planes of existenceu good rootsu good spiritual advisoru good wealth bodhisattvau gradual enlightenmentu great awakeningu great compassion mantrau great nirvana sutrau hagiographiesu hallucinationsu hearer vehicleu heaven and hellu heaven of satisfactionu heaven of the four kingsu heavenly beingu heavenly drumu hekiganshuu hell of uninterrupted sufferingu heretical viewsu heroic gate sutrau hoben hosshin son’eiu holy places of buddhism india you horizontal escapeu horizontal transcendenceu horner, ms i. Bu hsuan hua dharma master see: hsuan-tsang (596-664)u human bodyu icchantikau ignoranceu illusory but not non existentu immolationu inconceivableu indeterminate teachingu indra’s netu insight into the non origination of dharmasu insight meditationu intellectu interpenetrationu interviewu inverted viewsu jambudvipau japanese pure land schoolu jayanti celebrationsu jewel net of indrau jewels and gemsu ji schoolu jodo shinshu schoolu kalavinkau karmic resultu katyayanau kausthilau king of the dharmau kisagotamiu koan of buddha recitationu kokuzo bodhisattvau kumarajivau kumbhandau lamotte, etienneu lamps and torchesu land of blissu land of ultimate blissu lankavatara sutrau larger amitabha sutrau last disciple of buddhau law of cause and effectu le dynastyu learning and beyond learning stageu lesser vehicleu letting gou liberation in one lifetimeu life extensionu life provisionsu lifetime provisionsu light of asia, theu light of the futureu light of the worldsu lion among menu lion roaru lions among menu lokesvarau long and broad tongueu longer amitabha sutrau longer sukhavativyuha sutrau longevityu lotus treasury worldu lounsbery, ms. Constantu lu k’uan yusee: luk, charles (1898-1978)u macrobiotic dietu madhyamikau madhyamika schoolu maha prajna paramita sutrasu mahasattvau mahasthamapraptau mahavastuu maitreya societyu maitreya toweru mandara floweru mantrayanau maudgalyayanau maurya dynastyu medicine buddhau meditationu meditation on corpsesu meditation on deathu meditation sutrau merit and virtueu merit by associationu merit transferenceu middle way philosophyu middle way schoolu millennialismu mind lampu mind of discriminationu mindfulness of the buddhau ming, emperoru miraculous powersu modes of birthu monasteryu monastic buddhismu monks and nunsu mount gridhrakutau mutual identityu mysticism of lightu nagatomi, masatoshiu nalanda monastery / universityu nameless womanu namu amida butsuu nature and marksu nichiren shoshuu nine lotus gradesu nine mountain schoolsu nine orificesu nirvana sutrau nirvana with remaindersyn: nirvana with residueu nirvana with residuesee: nirvana with remainderu noble eightfold pathu noble silenceu north america buddhism in you notorious menu obaku zen schoolu obstacles to cultivationu ocean of landsu ocean of worldsu ocean seal samadhiu ocean wide lotus assemblyu oedipus storyu offeringsu ojo yoshuu omens of pure land rebirthu one flavoru one in allu one is all, all is oneu one lifetime liberationu one practice samadhisee: one-pointedness of mindu ordinationu organ donationu original natureu original vowsu ornamentsu overeatingu p’u t’o mountainu p’u t’o shanu padmasambhavau pali canonu pali text societyu parable: birth and deathu parable: bodhisattvau parable: boiling potu parable: burning houseu parable: child licking honeyu parable: demon and verseu parable: dukkhau parable: elephant and blind menu parable: human conditionu parable: medicinal herbs and treesu parable: phantom cityu parable: skillful meansu parable: spiritual powersu parable: stale rice /stale fareu parable: sufferingu parable: wealthy man and poor sonu parable: white pathu parinibbana suttau parinirvana sutrau path of the sagesu patriarchu patriarchal zenu peace and bliss collectionu perfect sudden teachingu perfect teachingu perfection of wisdomu permanently presentu persecution of 845 china you persecution of buddhismu personal provisionsu phenomenau pilgrimage sitesu pith of a plantainu platform sutrau polar mountainu post mortem omensu potalaka mountain india you power of knowing others’ mindsu prabhutaratna buddhau prajapatiu prajna paramitau prajna paramita sutrasu pratimoksau pratimoksa sutrau pratyutpanna samadhiu pratyutpanna samadhi sutrau precept schoolu precepts schoolu prediction of buddhahoodu primal buddhau proofs of rebirth in pure landu prophecy of buddhahoodu propitious kalpau provisional teachingsu pungent rootsu pure land mandalasu pure land patriarchsu pure land philosophyu pure land schoolu pure land school vs. other schoolsu pure land sutrasu questions and answersu questions of king milindau rahula, ven.