Because making a throw away twitter account is so hard
"Moreover, I attended an excellent high school that covered these fields of study in great detail, and I feel no need or desire to spend more time studying these things." If this is the case, then take the AP Placement Tests and you can skip those courses.
I'm not saying that there is no market for it, but you have to admit this is how a lot of companies will view it. Add to that the fact that, aside from MMO's, the PC gaming market is being eaten up by the console market. There is little enough money to be made in making games for Windows, even less for Linux. I wouldn't be surprised if in the near future the only kind of of PC games we will see are MMO's, everything else will be for console. It's just where the money is at.