I'm not really sure why people like gear treadmills. I played wow since launch and I stopped around the time the third expansion came out. I've always been a casual player so I only got to level 58 (60 was max) in vanilla. When tbc came out I didn't care about re leveling and getting gear much because I wasn't max before. By time the third one came out I was sick of having to grind for the best pvp gear again just so I could do well in pvp.
I think a gear treadmill is more enjoyable to someone is constantly playing a game. There are a lot of things I like to do so I can't justify putting that much time towards a game. I would have to stop working out, playing guitar and going out on weekends to compete in a gear treadmill. Then again I am waaaaay casual, I've been playing gw2 since launch. So far I have 1 level 80 and I'm not even close to getting a legendary (I've been saving up stuff the entire time too). I just barely got all my ascended amulet, accessories and rings. I can't even fathom how long it is going to take me to get the armor/ back piece lol.