AFAIK there's no technical reason why things can't be ported from Wii to PS360. The problem is that beyond graphics the Wii can't support things like larger levels, more complex AI, more enemies, etc etc that PS360 can, so even if you were to port the games they don't measure up to other third party games on those platforms.
There's also the issue of the Wii's wacky controls making games not translate as well, although Move has alleviated that to some extent.
*Edit* - But even with Move there's the issue that not all PS3 owners have it, so your audience there is limited.