Nuclear has huge investment since 1940’s and tonnes of money is still going into it. More money is not going to help anytime soon. It’s just throwing good money at bad. I’m not saying it won’t be cracked eventually. But with the limited time and money in the system wind and solar are obviously the answers.
Capitalism can easily solve the problem with externalities. Very few people that support capitalism wouldn’t also support government investment so the fact that capitalist governments have funded capital gains is not at all a failure of capitalism. That would be like saying governments funding schools to increase human capital to raise more taxes is a failure of capitalism. In fact it is the optimal solution for all even in a capitalist society.
There is always wind or solar. If you build enough of it they the low points aren’t that low anymore. There is still huge amounts of hydro on most continents. We are not even 10% of the way to where we need to be with renewables. The fact that they only offset gas some of the time doesn’t mean they won’t ever work, it just means we haven’t built enough yet.