The key problem is what was mentioned above - capital accrues capital exponentially, labour accrues capital linearly. The only way to fix this is to give everyone significant stakes in capital (or for the Marxists, the 'means of production'). The Norwegian pension fund, which owns about 1% of global equity is exactly the kind of thing that will be required to create any kind of future. Governments aren't the only organisations that can do this kind of work though. Any organisation that is giving workers the same kind of leverage that capital gets or sees that as part of its long term mission is part of the solution.

I see this as one of the greatest challenges facing humanity over the next few decades.

I would not say capitalism is broken, but that it needs occasional strict bounds by government to make living bareable. Market is not suitable as the only economic controller - state intervention is needed as well in the form of taxes and legislation to provide basic human conditions for the majority.

Recent decades have seen the rise of free market liberalism. I hope it is fairly obvious by now that unbridled this will lead to human suffering for many.

By what measure is it broken when it's produced literally orders of magnitude more improvement in human living conditions than anything in the thousand years prior to the advent of capitalism?