The more interesting question is: why isn't it on Wii, X2360, PS3?

The answer is very simple.
Anyone who asked for a port, yes everyone of thouse who asked. Where are your projects? Your finished work??
What do you have to offer to make a console port possible? Nothing... yes... I think so too.

Show them that you have something brewed together they just *MUST* have! The rest will be the minor problem. Goign the other way round probably is the most useless way. If you really want to program a console, go to DC Emulation, get the Linux toolkits and try and learn how to handle Dreamcast until you're ready for some real stuff.