Yep. A lot of the re-evaluations by publishers to release fewer games for systems has to do with their poor performance on a system in the first place. If I recall correctly, the majority of the games dropped by THQ were PS2 games that royally sucked, and had practically no sales after being out on the system for quite a while (enough that they know they aren't going to sell any more of them). So the cancellations were more of a "well, no sense in porting this game" than a "we don't like the Gamecube." The PS2 is becoming a sort of testing ground for developers, as in if a game does well there, it'll likely do well on another console, too. That's obviously more important for crappy games, or games that are sort of weird. The majority of exclusive titles for PS2 happen because developers do what I described above, and then Sony buys an exclusivity contract from them so they don't port the game. Which is sort of the reverse of what MS does. Sony has the capabilities currently to do that, with such a large install base, but it also means that the average quality of games on the console is waay waay down.
So, in some sense, it's good that the Gamecube isn't in first place, as developers tend to only release the games they know will sell well (which are usually games that are actually decent or better). Of course, it sort of sucks, too, as some of the really great games are not ported due to Sony's money.