There was no 'golden age' where nerds were popular and intelligence was always the most valued part of society. People aren't morons because they read about celebrity gossip or buy a ton of stuff or interact on social media. There was always a sizeable portion of the population who didn't care for intellectual parts of life, even back in the days of newspapers and radio broadcasts. Go back even further, and well, you were often deeply unpopular (at best) for having views considered 'dangerous' to society.
At least nowadays, it's easier to get involved in subcultures and groups for things you're interested in rather than being limited by geography. At least a lot of things previously considered 'for geeks' are now mainstream in some way. At least there's now a potential option for an intelligent outsider to make their fortune without having to be born into wealth or popular in a large company.
Anti intellectualism is not new, it's not increasing and it's certainly not bringing the 'downfall' of western civilisation.