Just my 2 pence, pretty much summarised what's been mentioned.
1. Broadly I have what I want. I'm riding, not building - and to be fair, riding is WAY more fun!
2. What I still want is proper rare so the likelihood of getting one is slim. So I'll just wait and wait and be back with a flurry if I ever get one of them.
3. It's the summer, there are better things to do!
Popularity will always change, that's life. Anything "vintage" is "in" at the moment so that's impacted us, not always for the better. But as long as folk keep riding the older bikes, there'll always be a "retrobike" - whatever that looks like.
Right now, pricing is ridiculous compared with a few years ago, in fact, even 12 months ago.
I do think the yearly update on retro would be good, or at least bring in new categories as and when. With some decent moderating and re-placement of build threads in could work. I think years would be much better than any other criteria so we get to see the best design evolution and cross-over.
The only theme I can't relate to is the old vs. new, preferring new and somehow linking that to fitness. It's just me, I can't relate to that - whether you have a modern or old bike - the fitter you are, the higher the chance you'll get more out if it. Again, just my two pence.