Muay Thai has already adapted. You'll always see it in MMA, just not to the extent it used to be. It'll still be a primary martial art. It's clinch work, usage of limbs, easier and more effective kicks are invaluable. However, it won't and shouldn't be the main source of striking work.
He was a bit older, but he's also fighting at MW where that doesn't really matter. I'm not saying he didn't slow down at all, but it wasn't his main problem.
Ehh, counter punching is mostly due to the nature of MMA. Lots of guys used to be afraid to lead with combinations in fear of being put off balance and getting taken down, so you got counters. Kind of like an over-reliance on Muay Thai, there is not much need anymore because most guys have good wrestling these days. Obviously you can't just freely do the same stuff as in boxing, but you see most strikers leading now and forming their own styles. Another thing you have to consider is the level of boxing skill in MMA has always been very low and is only just recently started to rise over the last decade. You can't expect proper boxers if a guy lacks good experience it takes to make one.
I agree with the wrestling part in the cage though, it gave a big advantage to wrestlers, especially those with poor footwork. Guys like Khabib wouldn't be nearly as successful. I've never liked it. If you can't get them down in open space like you have to in the circle, you don't deserve it. I wish they would go to a floored ring, but it'll never happen. Cage is most likely here to stay forever.
I think things will continued to be improved for many, many years to come. When UFC 1 began all of this was the realm of mystery outside of some serious martial artists and those who just liked to fight.
The science of the body motion and application of physics is an ongoing process.
The Grace's revolutionized (or popularized) jiujitsu and yet there is still so much that goes into mastery, or different approaches, Edward Clark Gallagher basically wrote the book on wrestling, however, many chapters are added as time goes on.
Now, on the part about the fear of combinations you are right and to be honest I almost mentioned that in my post.
The point
The "problem" is the Octagon as a barrier for grappling works great for trapping people, for aggressive strikers, brawlers, and punchers, it is an obstacle to enclosure.
The 8 sides make it to where whoever you are pursuing has two different angles from which to easily pivot and escape, or duck out of, a ring provides fewer compromises.
There is no corner to really corner someone in with striking in the Octagon, and that was by intent, the Gracie's knew what they were doing.
Why should I aggressively back someone down when there is no back to back them into? Not only that, the space and size make the effort of trying to find that angle all the more daunting, if not impossible.
