Not sure that there are many players of micros that actually spend a lot of time trying to improve. I think that happens only with the medium and high rollers. It's the same with any game or sport - most play it because they enjoy it and may spend perhaps a short time really going into it to improve. But it's human nature that few will actually manage to do that to any great extent.
I started playing 15 years ago and don't honestly think that the standard of play has altered much - there's a myth that USA players were the best, and that when they left online the standard dropped. My experience was that if anything the standard improved slightly.