With a game maker, it might be done within a week but with more limitations.
If you use high level tools and languages, you should be able to make a good game in one or two years.
If you search for the ultimate tools or pay too much attention to small details, you will get bored with the project before it is finished.
If you have more than 5 programmers in the team, 90% of the time will be wasted on poor communication.
I plan on getting started early 2013, and will be working alone. The game will be 2D and have some mediocre animation work.
Platform will be Android and programming wise I am capable, graphics/sound effects/UI design is not my strong suit.
The mechanics might very well be doable by a single programmer in a sane time, but creating the highly polished graphics, gameplay, user interface and content might not be easily achieved. If you know how to do those things properly however, you will likely get something that works after a few iterations of the features.
Creating a working prototype with the most basic of graphics is not a problem, I think I am capable of that. The involved physics should not be too complicated, the tough part is making it look pretty, as is with most games.