It's not a matter of whats going on that encourages the people to organize such compitetions, but rather experience I think. Shure Simply Maya can set up the comps, but how many people have the experience here to enter, and make it worth while?

Simply Maya seems seems to benefit the beginner and intermediate better than it does the expert. I'm not saying that there are no experts here, there are a few that are quite active here, but when it comes to challenges, the participation level is very low. So experience is why I believe there are no other types of challenges here. For some others is just a matter of availability.

Of course this is just my own opinion.