Plenty of people die daily in first-world countries that could have been saved in a different economic system, because saving them was not profitable. Even more die elsewhere, where the first-world countries have outsourced a lot of their miserable jobs. Cobalt mines in the Congo, used for certain lithium-ion battery chemistries for instance, have terrible working conditions and child labor. Another example is climate change: how many people will die this century from famine and water scarcity caused by a changing climate? Externalities don’t factor into capitalist profits, and the governments are usually under their control so they’ll just pay lip service to action or very slowly and reluctantly enact regulation.
Revolution is a one-time cost. It’ll suck, I hate it, but it seems to me like it’d be worth it in the long run. I’d also love to avoid revolution entirely, but that threatens capitalist profit so I really doubt governments (again, controlled by the interests of capitalists) will make it easy.
Another thing worth noting: revolution doesn’t mean financial markets have to immediately change. Companies can still act capitalist (at the start), they’d just be controlled by the workers now. Once workers own everything, and government infrastructure is set up to facilitate the sort of democracy and management communism would need, we can phase in changes. With control of the government, there could also be subsidies set up to help stabilize the market during transitions; for the US at least, there’s about ~$700 billion/year for the military as it stands, that seems like a sizeable fund to pinch from for such subsidies in the short term.