1. Why are you buying the console?
I'm not entirely sure i will. Certainly not while it is full price i wouldn't have thought, and probably not until there is a game that i definitely can't do without.
2. Has this differed from previous console generations?
Well i bought the Gamecube and Wii at launch, mainly because i thought they looked amazing and couldn't wait to play some of the games available with friends and family. The Wii U just doesn't have much of an amazing line-up to begin with...also, with the Wii, i bought it mainly for the multiplayer aspect. I barely played it on my own at all; while the Xbox 360 i play on my own all the time. I can see the Wii U not getting played much at all, like my Wii in the latter stages of its life.
3. Do you expect your attachment rate (how many games you buy for the machine IIRC correctly) to be high?
No, and that's the reason why i probably won't buy one straight away, as any games i do buy will probably not get played...
4. Do you plan on getting one of the future iterations of the other consoles?
It depends on what they are like. I'm very happy with my Xbox right now, as i can stream to it, play iplayer, etc, and use it as my main multimedia device. I can't see how the next generation can better it in terms of doing stuff like that. The only thing i wish my xbox could do that it can't is play blurays.
However, if it launches with some awesome games, then maybe.....who knows.