I'm not from the U.S., so as an outsider it seems to me socialism, which is the prominent political stance in some parts of Europe and a respectable opposition

I'm not from the U.S., so as an outsider it seems to me socialism, which is the prominent political stance in some parts of Europe and a respectable opposition stance in others, was/is constantly demonized there, similarly to how gay people were demonized decades ago ("recruiting" young children etc.). So a not-unreasonable guess as to "what's next" might be socialism, regardless of whether we're post-scarcity or not, and regardless of the success of basic income initiatives. Maybe ACA will be considered the first sign 50 years from now...