Why don't developers in the Bay Area use Mathematica?
Is it because it's not marketed to developers? Is it because of price? Is there a need for a general purpose data analysis platform?
That pretty much kills any sort of use for side projects or lifestyle businesses until after getting significant traction...by which time most people realize python and numpy/scipi is plenty good enough.
(Of course I'm not saying you want to base a business on that, but just that it's a cool way to get Mathematica and play with it.)
Now if I was establishing a hedge fund, maybe it might be worth it?