I think plenty still go out when they're students, judging by Coventry anyway. But my experience of teenagers is they're not so interested in it, so far anyway. My step daughter is 16, nearly 17. Some of her friends drink but she's vegan and it doesn't seem to really interest her. They all seem really savvy about drugs as well. Obviously things can change but from what I've seen the younger generation are less obsessed than I was.
I think maybe some people hit middle age and maybe get divorced then have nothing better to do than go to the pub, and probably have the income to afford it. As you're right, it's far more expensive that's for sure!