Its not the only one. Its the one that's proven to work from the 1st world to the 3rd world everywhere its adopted during the past 100 years with its warts and all. Capitalism with the weight of government on its back does weaken the game though, we have a pseudo-capitalism taking place now because of a very intrusive government controlling employment and an ever growing share of the GDP.
Government is now a major player on the field playing by its own rules, like never before rather than being the referee and arbiter of the game like it should instead.
Capitalism is an umbrella term used to describe a lot of economic philosophies. If you expect people to work for free; most of them won't. If capitalism to you is just getting paid for labour then, yes it's the only system.
Many people want to end the debate right there and say there is no alternative to the way things are being run now. This is what incumbent power prefers because any changes challenge it's power base. Once you have fought your way up to the top of the dog pile your next task is staying there by doing as little as necessary!
Statist economies run by ultra conservatives in Asian countries tend to do quite well and it's difficult to describe them as strictly capitalist. They are more like benevolent authoritarians who are generally hostile to business unless they cooperate with the government. This drives US corporations trying to break into Asia insane and they pressure the IMF to force change.
However the IMF really can't do much besides threaten their credit rating and they usually just answer this with threats of their own. Mixed economies in Europe tend to embrace a command style economy which embraces regulation. All capitalist countries tend to do this to some extent but Europeans sometimes rock the boat in ways people expect to end in catastrophe and ultimately succeed.
Germany forced the banks to buy shares in all major Germany industries. The banks were incredibly hostile to this because they preferred to invest in finance (ie lending money) but this ultimately worked well for the Germans because industry doesn't need to ask the government for money when they go broke like in the US. Their own shareholders bail them out!
Social democracy in Nordic countries is even more extreme. Regulation and unionism was so tight that everybody expected their economy to fall on it's face. Instead all the small businesses went broke and their own mega corporations took over in their wake.
Many people argue their economy actually became more efficient because the corporations are better managed and have large capital reserves to fund their own investment. Sweden has a very robust economy despite having the highest taxes in the world, strongest unions in the world and the most regulation in the world; really tending to prove that a lot of economic theory is just propaganda. All these examples are strictly speaking capitalism but not the type of capitalism that people think of in the US.
The main difference is in the US people tend to accept aristocratic values (liberty is more important than equality) and hence the aristocrats rule and do things their way. So long as the aristocrats don't get too greedy and share the wealth people accept this as fine.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.