The situation - and especially generationally - is the same across all categories of alcohol, not just wine, and so IMO it is not merely a matter of choice. The craft beer industry, for example, is in retreat. Also, people are not choosing to buy cheaper bottles of wine. They just aren't buying it. We saw the beginnings of this change in European grape and juice surpluses being destroyed as many as five or more years ago. I follow the investor side of the industry, and people were beginning to shy away from making financial commitments starting about that same time (which was lovely for my lil bit of wine stocks, lol).
There has been a decided uptick in the number and stridency of news stories about how any amount of alcohol consumption is bad for health, and more features about people like the ones in this video clip, who eschew alcohol (although pricey fake wine does not appeal to me; what's the point?). I think that more than anything else, that trend is having an effect, as well as the influencers that younger people follow.
The legalization of pot in, IIRC, 28 states has also had an effect on alcohol sales, IMO.
What's most interesting to me, though, is that the laws of supply and demand are not bringing down overall retail wine prices per bottle, even as bulk wine, grapes and juice have declined at wholesale. There's a lot of diverted juice and juice that is never pressed these days, and yes, it seems the industry will have to right-size, yet during this glut retail prices are still up there. As we winemakers know, commercial wine is a high margin, marketing-driven commodity. It would seem there would be plenty of room for prices to drop. But nope.
The most robust wine segment still appears to be the higher-priced bottles, as older consumers who still drink and have the resources continue to purchase those.