America falling behind is only a matter of time as MMA becomes more mainstream elsewhere throughout the world.
Think about it from an amateur perspective.
The costs associated with medical care in every single country on the planet outside of the U.S. are a non-issue, which to me would be a huge advantage from a development point of view considering the rigors of achieving that level.
Now that, coupled with countless other sports that actually pay really well in the U.S. (Shit, NCAA players can now get paid more than nearly the entire UFC roster) leaves only a handful of people, frankly dumb enough to want to fight professionally.
Whereas, somewhere like Dagestan, where combat sports make up the bulk of their cultural exports and is likely subsidized to an extent, fighting professionally is probably pretty desirable after a childhood spent wrestling.