> And fashions also come into play in these judgments. I will eat my 8G-networked collapsible VR headset if, 20 years from now, people aren't horribly cringing at the popular 2020 notions of "solving climate change" and "working for racial justice".

Are people today horribly cringing at the civil rights activists from the 50-60s or gay rights activists from the 80s-90s?

I think people are far more likely to cringe at naive optimism (e.g. postwar enthusiasm for heavy industry and its products) than genuine attempts to tackle problems.