There's taste and then there's taste

Popular taste is guaranteed to be awful since it is driven by economics and fads. That's the type you point out as created by the market and catering to the young. It's a disposable product of consumption used to sell shoes and overpriced paintings.

I don't disagree that it will permeate everything, it already does. It'll just be written by an AI instead of people being paid to find the next style to cop. I don't think it will extinguish human writing, you'll just have AI writing that you feed to official or public channels and then real writing that goes in private or pseudonymous channels. Using AI writing among friends or an in group will still be a faux pas and cringe because it will have become the norm to be rebelled against.