There are changes to poker all the time. Not so much in the written rules of the game, but in the way the game is played. I'm thinking of things like limping into a pot, 3-betting, check-raising, etc.
Strategies change and you start seeing actions at table that you didn't see previously. Also, agree that more access to books/videos/forums about poker make the general
online poker community more knowledgeable and make the games harder to beat.
I play more online than live, and understand that lower limit live games are still pretty soft. Not saying that there isn't a way to beat lower stakes online games, but they're nowhere near as soft as they used to be.