We attract people who want to solve interesting problems, or to build markets faster than closed source can. Both these motivations are certainly relevant to the GUI problem. Not very, in my opinion. I believe the competition in design approaches is good for both projects. You've had good things to say about sourceXchange , set up to bring hackers and funded Open Source projects together.
Prediction is difficult.
I don't know the answer to this yet. The Linux-Windows rivalry now has center stage. I don't think so. As I observed earlier, one of our strengths is that we have enough smart people to try everything. Many people are focusing on competing with Microsoft.