A: Because it's much more "intellectual and inclusive" sounding to say you listen to NPR, and they're subsidized by our tax $$$$. NPR is kind of like alternative energy programs. It wouldn't make it either without the government subsidies.
Q: How does one make a small fortune with liberal talk radio.
A: Start with a large one.
Excellent point. A for profit liberal talk radio station has to compete with subsidized NPR