You have to ask fsh that question.

My point is that so much talk against it, and yet there isn't really worthwhile competition.

Ok, I agree with you. I own a copy of Mathematica myself. This topic just very much interests me, because there is this dilemma with this kind of software (I am working on something like that myself): It is so much work, you need to charge for it; on the other hand, for widespread adoption it probably needs to be open-source. What do you do?