NNTP, so awesome until 95% of its resources were consumed by its abuse as a file sharing platform for (naughty to nasty) images and pirated software and until power-hungry local group moderators started abusive banning/deleting practices against people who disagreed with their opinions on politics etc.

People want their own fluffy & safe social bubbles, not open, distributed networks.

Because Yandex and Baidu give your data to some of the worst governments in the world.