Again, I don't know what you mean by "capitalism", but it's simply not that case that "we can only take actions that benefit individuals in the short term". In the US context, it's certainly true that many companies make many decisions that are driven by short-term profits, but they also make many decisions that are driven by longer timelines (e.g. capital expenditures). I think the same holds true for non-profit entities, including governments (it's a mix of short-term and long-term thinking).

I think a better line of attack is that externalities are poorly accounted for in our current economic system.