Maybe your memory needs refreshing: 1. The Fed kept interest rates too low, making credit easily available. 2.
People started borrowing to speculate on homes. People who could not actually afford to pay these mortgages. 3.
Fannie Mae and Freddie Mac bought lots of these bad mortgages, so banks could make even more bag mortgages 4. The investment community figured out how to package these mortgages into securities, so banks could make even more bad loans. 5.
Companies like AIG insured these toxic investments without realizing what they were doing, and not putting nearly enough reserves to pay off on them 6. Credit rating agencies gave these investments AAA ratings because they were insured. 7.
Then people stopped paying outrageous prices for homes, the bubble popped, and lots of people were holding bad loans and investments they couldn't pay. Now in all of that, do you see anything about how tax cuts were involved for good or ill?
It could have been worse without the tax cuts. Since we had to borrow money to pay for the tax cuts, you can say that the economy was sustained by the borrowing. Bush had no economic policy except shipping jobs overseas.
The only thing that kept the economy going was low interest rates and the housing bubble. It allows people to get second and third mortgages so that they can spend money like there is no tomorrow. When the investment banks fail because of toxic assets, the housing bubble burst, collapsing the economy.