I don't know about the UK anymore but over here bike riders just keep growing every year. Presumably a result of the post-Soviet era when only Russian and Jawa's were available. I stay off the local bike site as I'm considered an old fart riding an antiquated bike - though the bike has been the centre of attraction at MC fests I've been to.
Here the younger generation (OK - kids to you and me) go for the Nip bikes and speed or scramblers. Plenty have admired the Bonnie but don't have the money to buy a new one, so they go for secondhand Nips imported from Germany or elsewhere in Europe. The better off crowd tend to go for HD's.
Interesting point - seen a good few home made bikes with old Russian car engines. Some are quite slick.

Ernie.