His lies/alternate reality are not so much believed as embraced - the people who support him already loathe and hate the things he’s talking about. All he’s doing is lending them legitimacy. Most people are, by and large, reactionary and seek out things and people that confirm their own beliefs. Nothing here is new apart from the scale of it and the new technical ability to increase that scale.
And it’ll stay that way until people use, and keep using, this space. So, to use an overused phrase, be the change you want to see :)