Bill's only real talent is that he believes in himself. He was a good writer. I haven't listened to his podcasts in awhile, but he isn't a particularly deep or unique thinker, and if he has someone on who pushes back on him; he goes to pieces. Despite saying how easy it is to host a TV show, that was an unimigated disaster. He also didn't seem to be good at writing jokes for a late night show, despite years and years of saying how easy that gig is too. I will say that he's good at finding talent. And he's good at making friends with important people (Jimmy Kemmel, John Skipper, to name a few).
As far as the 30/30 documentary series, it was fine; but at the end of the day it was a series of sports documentaries. They didn't hang together (despite his mission statement of "finding the untold and forgotten stories of the last 30 years" and opening with the Wayne Gretzky trade) and while good (and sometimes great), they didn't revolutionize the industry. They could have been on FOX Sports or HBO or a million other places.
IDK, if your metric is that Simmons is good because he makes a lot of money; I won't argue with you. Dude is fucking loaded and has done very, very, very well for himself. If your metric is that Simmons is entertaining, again I won't argue with that. Podcasts are so personal and intimate, if you connect with Bill and his friends, I can't argue with that either. And there is a talent there, I suppose; but it's a medium talent at best. He's just good at promoting the Bill Simmons brand.