The capitalist system is the one we have now. Even people who dislike it and want it changed have to live within the system as it currently exists.
Has anyone even formulated and proposed any notionally viable alternatives? Apart from the vastly destructive and murderous attempts of communism in the past century.
Not saying the implementation of the current system is optimal, of course, but I think over time things tend to converge on that which does the most good for the most people.