Whether the overall difficulty for the average player has changed is something I'd say is impossible to prove one way or the other. It may not be much easier to be rank 1 today than it used to be, but top 20 for example means way way less today than it once did. When I played most uk worlds it seemed the top 1-2 players grew at speeds reminiscent of .net top 20, but past that there was often a large drop off.
I fundamentally disagree with your %'s though. I consider good players to be around 1-2%, and "elite" to be less than 0.1%. There is a head and shoulders gap in understanding of game mechanics between the top players and the pretenders.
Example: Speedmerchant, who made this thread: I'd consider him a good player. I rimmed him on uk6, he fought back valiantly, he lost, but he displayed a solid understanding of the game when fighting me. He split my train, he backtimed the nobles that lived, he then attempted to noble my newest village off of me, he forced me to split his train and suicide all my troops in the new village to just barely kill his nobles (it didn't have enough troops yet to clear him even when backtiming him, there was only a 43 hour gap between nobling it and finishing off speedmerchant). He lost, but he did what he could to have a chance.
Star123 was the player I rimmed before I rimmed speedmerchant, it was star's village that speedmerchant tried to take from me. Star did not attempt to split my train, he did not attack me, he did not show any semblance of timing capabilities, he just stacked, and because he couldn't get enough defense he got rimmed.
As such I have far more respect for speedmerchant than I do for star123. Speedmerchant is a more complete player. Star is a grower, you can even say he's a good grower, but he's not a complete player. He might be rank 1, but he's rank 58 OD, nobled 52+ internals and 1 barb. That's at least 53 free villages, and he only has 91 villages so at most 36 of them were taken from people that fought back. I say at least because some of the tribeless conquers may essentially be internals too, but I don't care enough to check the tribe changes of all of them or make speculations. That's not how a good player plays.