Speaking of time and compatibility with different hardware; each time you port to a new system you'll have new bugs to fix. In a program as big as Maniaplanet you're going to have a lot of bugs period, and a lot of bugs that are going to show up on porting to new hardware, I'm not even mentioning architecture (because I don't know enough about system architecture, my latest class only touched on toasters...

). Bugs nobody's bothered about or even noticed, because they don't appear on the systems that Maniaplanet runs on; bugs whose fixes will cause compatibility problems between systems which will then need to be fixed... (although from what I do know that is the sort of problem more likely to be caused by architecture.)
Once you've fixed those you need to convince Sony to support a game that will be compatible with the same game running on a Microsoft console, and a Nintendo console. And convince Microsoft and Nintendo of the same. Which would be like Zico vs Karx to the zero of you who know what that means. Except, probably even more
political... You can imagine the time that will take. All none of you.
Although with consoles there is the advantage that you don't need to run an enormous beta, since all 360s, for example, have exactly (or nearly exactly) the same hardware.
How do you think map sharing would work on consoles, btw? Not the way it worked on TM Wii; I hear that was a total disaster...