You're not really making any points here.
First of all, the COD4 vs. ODST comparison. Completely invalid. GOTY is a repackaging of the game selling to new users for the game. There is no reason for existing COD4 users to run out and buy it. Conversely, ODST is an expansion on Halo 3. The fact that it includes the maps from the original game plus the maps that are already free plus the additional DLC is of little consequence. The intent is to sell (most of) this crap to people that already own it!
You get a short, forgetful campaign, you get a new multiplayer mode (without matchmaking, which is a complaint for some and would be for me if I cared to play it but since it's an extension of the campaign, I'd rather not), and a bunch of maps that the majority of which you already own.
The value just isn't there unless, as stated before, you never bought Halo 3, in which case the value might actually be a steal. Once again, good job to those 8 unique people that bought ODST and skipped 3.
Anyway, the point is moot. Something like 2.5 million people have bought ODST according to USA Today, so the train's left the station and has made Microsoft a lot of coin.