Trends are largely consumer and rider driven and proven long before they go to production so I'm skeptical that any advancement in frame geometry is merely throwing numbers into the wind and seeing where they land.
For what it's worth, short wheel bases and high bbs were driven by riders almost 2 decades ago to meet the demand of riding skinnies and ladder bridges with low speed steep exits and sharp corners. Since this type of riding has all but disappeared, the need for such bikes has followed suit.
Today's style of riding is not only faster due to new trail types being constructed but also due to the level of skill the new generation of riders exhibit and the preferred trails they ride. Faster speeds require stability which comes from some geo changes like lower bbs, longer FCs, and slacker HTAs.
If you're pining for old school bikes, better start cruising the buy and sell for 2002 VPS frames. Probably not too hard to find something.
If you re-read what I said, maybe you'll notice that in some respects at least we agree :)
My current main ride, which I designed myself happens to have pretty well all the current trends, and one can get away with a low BB on a hardtail (not that RMB know anything about them any more :P ). It does seem though that some bike companies seem to forget the 'normal' riders. Sure, people test bikes but who? John Smith or Wade Simmons? I've heard constant moaning about low BBs on AM / 'enduro' bikes since 2006 and they keep getting lower. When will it end?
As for new styles of riding and new trails, you mean the same ones as the early 90's (in the UK at least). Just shredding singletrack as fast as possible. Nothing at all has changed there. Hell, we were even 'freeriding' in quarries in the UK in 1989. I just think it's funny that bike companies market full on race bikes to people who'd be way better on something a bit more forgiving. Much as I sort of hate endless categories of bikes, I quite like the fact that road bikes tend to come in 'race' and 'can race but with a hint of comfort and less likely to throw you on the floor' styles. With high end mountain bikes these days all you can really buy is a Ferrari.
I do actually have an old school ride….but the BB is 'only' around 360mm and on the Shore that feels great to be honest. If I was riding anywhere else though I'd probably go to 340. Lower than that can GTFOIMHO.