One thing that's changed in the last 20 years is the rise of social media. Some voices are heard loud and clear, drowning out those of people of any age who don't spend their lives curating their profiles, etc. Fashions grow, spread and die with incredible speed, in part due to influencers, who are paid to sell stuff to people, so the more new products they introduce, the better. New versions of consumer disposables appear with amazing rapidity.
This comes on top of a massive change in the last 70 years or so with regard to two things: (1) people are older when they settle down and start a family; (2) there are more people in education over the age of 16, often to age 21 or even beyond. Hence more people in developed countries have a period of 10-15 years when they do not have a family to support and/or take care of, but they also have some disposable income, either from parents/guardians or from working full- or part-time or both.
(The extreme here is "pink pound" or "pink dollar"—the money men have when they are gay, in employment, often with a partner also employed, but no children to support. Lots of disposable income there. Palm Springs has been transformed in the last 20 years by the pink dollar. There is a lesbian community there too, of course, but men tend to make more money, gay or not.)
These factors combine to explain how outlets that don't directly depend on advertising, like the BBC, have been captured by Da Yoof and their combination of dedication to ephemera with rigid essentialism. Gender identity answers both needs: it's absolutely who I am, but it can change everyday if I want it to, so there. The BBC thinks it has to pander to this sort of thing, not realizing it is alienating its older viewers (and some younger ones) while still coming across as mutton dressed as lamb.