You'd think, and yet I'm very interested in Pathfinder*. I don't think 3.5 -- er, the second most-recent edition -- is perfect, not at all. I am almost certain WotC could have kept me as a loyal, crazy-spending customer, by fixing that edition, rather than creating a new game. That's why I'm so confused about why they didn't.
I think the answer has two parts, the specific, and the general.
The specific is basically what Toben the Many said. A lot of people had problems with 3E, and 4E made changes to fix those (percieved) problems and improve game play (for some). I think its worth noting that this is not really about WoW, Hasbro, young, old, DDI...a lot of people in what I am guessing is the exact same demographic as you, or at least many ENWorlders (typical 30 something pale skinned male english speaker playing D&D since early 80s) have found that 4E improves game play, and like it better, and will buy stuff for it in a way they no longer did for 3E.
But you didn't, and you don't. This leads to the general point. So much stuff for 3E had been released (and it is an incredible amount, by way of comparision, I have a pretty complete 1E collection, it takes up, oh, 18 inches of shelf space, at the most, while my very partial 3E/D20 one takes up much more) and bought by so many people, that WotC didn't really have a choice but to do a big revision. 3.75 would face too much competition,
from what they have already released.
D&D just doesn't have the number of players, and hence raw volume of a, say, monopoly. (to touch on an earlier post) And you don't really need that much for it. But WotC wants to sell you a bunch of stuff. So they have to do better. They have to do a big revision that makes what they released before "obsolete". This revision naturally responds to a lot of problems (some) people have with the game.
But you didn't think the game was obsolete. Which leads us back to your problem.