I knew that i was more talking about they already had a basic information at hand, and to me I would of thought that then new cartridges (even though they are smaller) would of had more of an ability to hold more data then the old N64 cartridges. But dang I feel totally trolled
It's got nothing to do with data storage capacity.
The DS cards can store a lot more data than N64 carts, the issue is that you can't just take the code from the Stadium games and use it in Pokemon on DS or 3DS. Even if Nintendo used the exact same methods, model types, data storage methods, animation methods, etc, etc, etc (which, simply put, nobody in their right minds would do for another long list of complex reasons) they still wouldn't be able to just transfer it, the code would have to at least be partially rewritten, if not totally rewritten and even then the quality of everything would be a lot worse as they're using all the old things specific to the N64 (limits of processing power, chip architecture, 3D capabilities of the time, programming styles, general hardware, underlying software, etc) so it the animations and models would all be N64 quality, possibly worse as a result of having to port everything.
So yeah, again, long story short: the N64 code for animations is pretty much useless any way you look at it.