Christ, you play it for hours every day and more on the weekends, and think this isn't hideously excessive?!?
A few hours a day - not every day, even, he takes a few off here and there - and a little longer on the weekends isn't excessive. Online gaming actually cut down my "lazy" activity time and cut costs. I wasn't plonked in front of the TV (cancelled a few cable packages, rented fewer DVDs), I decided to spend more non-game time away from the computer and/or TV (read a bit more, got out of the house), and on top of all that spent more time with the better half (playing the game together, chatting while we did, etc).
Yeah, sometimes you don't get to play or TV or whatever for a while, something more important is happening. We stopped playing for a few months last time we sold the house, we had work to do when we got home. Online gaming is only excessive when you fail to keep up with life's priorities (job, home, health, family, friends). Ditto any other gaming, TV time, internet surfing, hardware hacking, wood duck carving, drinking, drugs, food, jogging, etc etc etc. It's usually easy to keep it all in balance, and part of what WoW does well is deliver a game that you CAN walk away from, to focus on the important things, and still keep up with the game.
It's not so much that "Casual" gaming is influencing MMO's, as it is that game publishers recognize that a lot of gamers are all adult-like now, and if we can't integrate the game into our real lives, we're not giving them our money. And money - the market - is what influences MMO's.