TootyR this one is interesting...'...Your also right, modern bikes are not for xc peddling....they are for throwing down a hill, so im not surprised that the geometry is completely arse about face to a early 90s mtb'.
Your are right about a certain period, but my experience in the last year has been very different...
You are right in respect of many 'progressive geometry' frames and bikes from 2010-20. There was a lot of attention to head angles during that time, and more travel was piled on the front, using slacker and slacker angles - going from 70-69 as far as 63 degrees unsagged. On these bikes, I had to bail from climbing on well-known slopes which I would have 'made' on my 1990s hardtails. The main problem was radically-wandering front end and no way of readily finding a sweet spot between front end control and back end traction.
BUT
Then it seemed that good designers put their mind to the back end of bikes as well as the front end - ie considering the interaction of all the elements of a frame. In 2020-21 there has been a lot of good stuff going on. Transition - (west coast Canada) - introduced SBG (Speed Balanced Geometry) - which required small offset forks (typically 43-44mm), a steep seat angle (75ish), slack front (65 sagged), short stems (35mm) and rangy reach (450mm for me). For sure this was belting when pointed down, but also allowed really competent uphill cranking - the slopes on which I was bailing using pre-20 progressive biked suddenly became a breeze. No wandering front, plenty of rear traction - and a large sweet spot to stand or sit in when climbing. Likewise the Stanton Switch29er, which I have riding a lot recently. My brace of progressive bikes from the pre-20 era struggled to be convincing climbers. The Transitions and Stanton are a deep contrast to this...they climb. Oh how they climb. The short fork offset is a major factor in taming wandering front end combined with steep seat angles and the curved seattube allows tight rear triangles which give huge grip. In fact some climbs just/barely possible on 1990s frames suddenly became entirely do-able, particularly rooty rooty rock step climbs. And of course these bikes wake up when pointed downhill. OK you might say....but I wouldn't ride these on all-day distance-fests. The Transitions are FS, and not really distance-munchers, but the Stanton is really up for it and a bike I would reach for if I was doing a 100-miler.
In my view
The early mtbs were fun...but very limited (my Dawes Ranger was huge fun...but frightening at anything above walking pace)
The 1980-and 90s saw some really thoughtful geometry (Kona, Marin Teams) which worked...really well...and pushed performance
The 2000s saw a lot of innovation which made bikes good at one thing
But today we see highly mature geometry which is yielding some stunning all-rounders
The view from 1990 - I want an Explosiv since it is a great innovation in geometry
The view from 2015 - I want an Explosiv since it is one of the best performing retro-bikes and cheap
The view from 2020 - I want an Explosiv since it's one of the best performing retro-bikes but I can barely afford it
The view from 2025 - A Stanton 29er ti will be in the future be regarded as a brilliant retrobike, alongside things like Explosivs
The view from 2035 - I want either a Stanton 29er ti or an Explosiv - they both are brilliant retro-bikes