I think the major cause for this is the self branding phenomena that started together with the social media boom. Suddenly people got it to their minds that they are supposed to market themselves like products. And with the best tradition of PR, the truth don't matter, only the optics. So you got a bunch of mediocre engineers, some hardly out of uni swamping the net with opinions and shoddy advice , written in a very knowledgeable tone, because "that's the game". Combine this with tons of tech startups using same PR technics to sell their often than not, less than perfect technology.

With the crazy boom in developers, you got a whole generation of mediocre devs without any tradition to build on, surrounded by silly opinions and fads to learn from.

Now replace "developers" with any information age occupation , this remains true.