"Gravel bikes are just 90's mountain bikes"
It's not just that it's a lazy trope spewed out by thirsty social media trolls - it's that they say it as though it's a bad thing.
The reasons they aren't, are so many and so obvious, I won't bother recounting them here. But frame materials, brakes, wheels, tyres, gears, and every other component are all orders of magnitude better than their 90s counterparts. So what's left? The geometry. It's no secret many 'modern gravel' bikes' geometries converge to a point of great similarity (if not singularity...), which is no accident nor coincidence. There's also no hiding the fact this ends up rather close to typical 90's MTB geometry.
There's a reason for that - they ride great! 90s mountain bikes were (and are) amazing. They are nimble, agile, climbed well and were comfortable and efficient enough to ride all day. They flexed, they shimmied and they sometimes they juddered, but man they were fun. The brakes were rubbish, flat tyres were just a fact of life, bent wheels and chain suck were commonplace. Advancements in all these things make modern gravel bikes so much better than your old Rockhopper it's not funny. But what the best of these modern bikes haven't lost is the simplicity, responsiveness and versatility those great 90s MTB's gave us.
The 90s were also, for many of us of a certain age, our youth. Mountain bikes were fresh, new and exciting. They gave us a freedom to just go and explore: the woods, the farm tracks, the big fire roads, the occasional bits of singletrack. Anything was possible, trail access wasn't (mostly) an issue, you could just ride. We rode, raced DH, XC, trials all on the same bike. We toured on them, commuted, just rode to the shops. We made habits and friends for life. Riding was a joyous thing - not something to be measured out in watts, calories or the size of that gap you dropped. Finding a whole genre of modern bikes which brings back some of those feelings and give us that range of versatility and fun is to be celebrated and relished - not decried.
What would be the alternative? To throw away these simple, practical versatile bikes? Pass an edict saying 'no head angle shall be steeper than 70 degrees'. Force everyone to be riding long and slack mtb's with 0mm stems and yard wide handlebars?
Gravel bikes have a similar silhouette and geometry to 90's mountain bikes - and that's a beautiful thing. So the next time someone drops a 'nice gravel bike, looks just like my '93 Stumpjumper' on you, smile and nod and say "yeah, they were awesome bikes".