I'm amazed how embittered people are over this. The GC has proven to be a poor platform for third party publishers. Get over it. Nothing is going to change that in its lifetime. As a result, the next Nintendo console will also face an uphill battle to draw support away from Sony. The same can be said for Microsoft's next console, although it will enjoy a stronge starting benefit of the doubt from US developers who've done decent if not great business on Xbox.
It all comes down to numbers. Which machine has a cuter name or a prettier box, none of that matters to a third party publisher. The #1 consideration when choosing which platform to support is installed base. This is so much more important than all other issues that you can also list numbers 2 though 5 as installed base, too. Then you can start thinking about things like the technical requirements of the game, demographics of the possible platforms, etc. Those machines sold make all the difference for the smaller boutiques publishers, such as Atlus, particularly. When you have a title that might only reach 1% at best of the US installed base this is the difference between 300,000 PS2 units and 80,000 GameCube units. The difference between a viable title and a money pit.
The Monkey Ball series is a good example. Sega originally chose to make it a GameCube exclusive. They were newly finding their way as a third party publisher and tried distributing exclusives by the apparent demographic match of the respective platforms. Monkey Ball seemed best suited to Nintendo's youth and family orientaton. This failed to pay off and Sega is now porting a compiled version of the series to the two competing systems. It is almost guaranteed by virtue of sheer numbers that the PS2 version, even at its low price point, will be more profitable in the long term than the GC version that launched with the machine. Sega also has an Xbox version coming. This is more of a risk but the cost for porting an existing title with low technical requirements is low compared to creating a new Xbox title from scratch. A bigger worry is the Xbox's low numbers, which are little better than the GC's. Mitigating this is the much greater uptake of third party titles by Xbox owners.
Demographics are a difficult business. Early on, most publishers wouldn't put a kid oriented game on the Xbox. So Harry Potter and Songbob Squarepants were on the unavoidable PS2 and kid-friendly GameCube. A couple years passed and the sales numbers told a different story. Now the first two Harry Potter titles got Xbox releases long after they'd peaked on the other machines and simultaneously release across all platforms for the latest entry. Spongebob has followed suit and the movie tie-in game will be another all-platform release that might have skipped Xbox just a year earlier.
So the Xbox has managed to deliver sales in spite of its having less than a third of the PS2's numbers but the GC with similar numbers hasn't. Even so, there are a lot of titles that aren't going to get ported to Xbox because it cannot deliver sales in the Japanese market where those titles are strongest. If a Japanese publisher has a project with greater potential in the US and Europe it's the opposite situation but thems the breaks. Those few Xbox owners in Japan will at least be offered an untranslated version that runs within their region.
Why can't Nintendo deliver sales to third parties with an installed base comparable to Xbox? I believe it's demographics again. Regardless of present company, the average Xbox owner is older and more likely to have a significant disposable income compared to the on average much younger GameCube owners who are more dependent on the generousity of adults for expanding their library. This might also inhibit the the sales of more mature titles. not because the GC owners themselves don't want them but because the clueless gift giving relatives are playing it safe and sticking to the big Nintendo franchises.
It all comes down to numbers. Which machine has a cuter name or a prettier box, none of that matters to a third party publisher. The #1 consideration when choosing which platform to support is installed base. This is so much more important than all other issues that you can also list numbers 2 though 5 as installed base, too. Then you can start thinking about things like the technical requirements of the game, demographics of the possible platforms, etc. Those machines sold make all the difference for the smaller boutiques publishers, such as Atlus, particularly. When you have a title that might only reach 1% at best of the US installed base this is the difference between 300,000 PS2 units and 80,000 GameCube units. The difference between a viable title and a money pit.
The Monkey Ball series is a good example. Sega originally chose to make it a GameCube exclusive. They were newly finding their way as a third party publisher and tried distributing exclusives by the apparent demographic match of the respective platforms. Monkey Ball seemed best suited to Nintendo's youth and family orientaton. This failed to pay off and Sega is now porting a compiled version of the series to the two competing systems. It is almost guaranteed by virtue of sheer numbers that the PS2 version, even at its low price point, will be more profitable in the long term than the GC version that launched with the machine. Sega also has an Xbox version coming. This is more of a risk but the cost for porting an existing title with low technical requirements is low compared to creating a new Xbox title from scratch. A bigger worry is the Xbox's low numbers, which are little better than the GC's. Mitigating this is the much greater uptake of third party titles by Xbox owners.
Demographics are a difficult business. Early on, most publishers wouldn't put a kid oriented game on the Xbox. So Harry Potter and Songbob Squarepants were on the unavoidable PS2 and kid-friendly GameCube. A couple years passed and the sales numbers told a different story. Now the first two Harry Potter titles got Xbox releases long after they'd peaked on the other machines and simultaneously release across all platforms for the latest entry. Spongebob has followed suit and the movie tie-in game will be another all-platform release that might have skipped Xbox just a year earlier.
So the Xbox has managed to deliver sales in spite of its having less than a third of the PS2's numbers but the GC with similar numbers hasn't. Even so, there are a lot of titles that aren't going to get ported to Xbox because it cannot deliver sales in the Japanese market where those titles are strongest. If a Japanese publisher has a project with greater potential in the US and Europe it's the opposite situation but thems the breaks. Those few Xbox owners in Japan will at least be offered an untranslated version that runs within their region.
Why can't Nintendo deliver sales to third parties with an installed base comparable to Xbox? I believe it's demographics again. Regardless of present company, the average Xbox owner is older and more likely to have a significant disposable income compared to the on average much younger GameCube owners who are more dependent on the generousity of adults for expanding their library. This might also inhibit the the sales of more mature titles. not because the GC owners themselves don't want them but because the clueless gift giving relatives are playing it safe and sticking to the big Nintendo franchises.