i go by the end result rather than theory. Philippines and Nigeria are 2 end results of capitalism. 16 hr work days, low pay, no safety, kids working, etc are all common in these places, these were also common in the US many years back under capitalism.
the theory IMO does not work as well. a painter, carpenter, factory worker will never compete with the business owner, their only concern is providing for their family, the owners only concern is making money. as the system moves on the owners get more and more while the workers get less and less. this can be confirmed in the history of the US, 50 yrs back a worker made much less, technically they made more ( 200 a week verses 500 a week now) but back then your check was worth 500 gallons of milk where as today its only worth 300. the system is fueled by greed which leads to more wide spread poverty. walk through a city in the US and then walk through a city in Europe and you can easily see the difference.
socialism is not the answer, IMO the best answer is not a free market but a limited market, free market with lots and lots of rules, when you remove the rules (regulations) the rich money mizing elite will take everything. think of a monopoly game.