If I remember your age correctly, you’re not old enough to make a sweeping statement like that. Do you even remember the pre-internet era? Yes people have always bought newspapers that conform to their pre-existing political views, and people naturally socialize with likeminded people. The difference is that with the mass explosion in cable TV offering vastly more choice for partisan news sources, and more importantly the new social media phenomena where people are seeing a constant barrage of extremely partisan propaganda, they don’t have a reasonably unbiased arbitrator of what is real or not. In the past people might read the Guardian or the Sun but they were almost without fail also seeing one of the mainstream TV news shows like the BBC which provided a stabilizing influence. Now we see people denying the reality of those sources in a way we just didn’t see before. ‘Fake News’ wasn’t a Trump invention, it has been a slow and steady delusion that the internet has played its part in spreading. Now we’re seeing the previously neutral internet trusted fact sources like Snopes come under heavy attack too, largely based on social media attack campaigns intended to undermine their reputations to allow the flow of disinformation to spread even more freely. We’re literally living in a time where a majority of people can believe things that would once have been the preserve of extremist whackjob conspiracy theorists, and that is massively the fault of social media (reinforced by cable TV).