At first it was BJJ that proved to reign supreme. If you didn't know the fundamentals of BJJ you were pretty much gaurenteed to lose a MMA fight.
Then came the wrestlers who learned the submissions of BJJ and how to avoid them. They created the Ground and Pound game and were able to control the fight by their superior wresting skills.
Then along came the kickboxers who learned to avoid and stuff the takedown of the wrestler/bjj guy. No longer were opponents clueless about the takedown and clinch.
Now MMA is just that, truly a hybrid sport. There isn't much chance for success unless you can do all three things well: strike, work in the clinch, and know groundwork. The scariest guys now are the wrestler/grapplers who have a very strong stand up game (in other words extremely well rounded fighters).
Do you see MMA having any real evolution in the future or will MMA basically be the same 25 years from now?