There are several drivers of mountain bike design that have changed them a lot in the last ten years. I think the most popular events right now are enduro racing, where the riders must pedal the course for the entire event, but the uphill parts are liaison stages. They are only timed going downhill. So they require bikes that are fast downhill and comfortable uphill. The final event of this year's Enduro World Series was 1500 m vertical in 58km... but only 8.5km of dowhill in four stages. They resemble downhill bikes but are not quite as extreme. This style of bike has proven pretty popular with regular schmucks who get to ride on Saturday or after work, and shorter travel bikes for bouncing around in the woods are now less-extreme versions of the same approach. Even trail hard tails now have slacker head tubes, more reach, and a little more fork travel.

XC racing bikes, which were once the big-tent category, have meanwhile become really dedicated racing machines with no compromises for versatility. Some of them are still hard tails and some have a clever bendy frame, some are full suspension, not everyone is on droppers. But I think nearly no one is buying this style of bike any more unless they want to go racing with it.

A second trend is bikepacking. The bikes for this are laid out like really conventional flat bar bikes for seated pedaling. What's changed from road touring bikes is the way the bike is loaded. Some of the camping gear is taken from through-hiking (a minimalist form of backpacking) and some of it, especially the triangle and seat bags, is now carrying back to road touring bikes.

And of course the another big fad is e-bikes, which has taken the heavy-duty enduro hardware and used it to absorb more speed on the level and climbing.