I often wonder why we don't have a vibrant, live music community in San Diego. It isn't the worst I have found, but it just doesn't hold a candle to the scenes in Austin, Nashville, San Francisco, and New York.
I believe the problem is with our local government. It is so difficult to get a liguor license that allows live music. This means there are only few places that can have a live band perform. With a limited number of venues, it is difficult to have a tiered path to live music success. Sure, The Belly Up and The Casbah are great venues with loyal followings. However, they support touring acts to a great extent. There are smaller venues, such as The Kraken in North County, but they pay so poorly, really good musicians won't play there. Casinos pay well, but they cater to people that aren't really music lovers.
The beauty of the great music cities is that there are blocks of venues with live music. Walk down the street in Austin or New Orleans, and you will hear a lot of live music. You get to discover the talented bands with your ears and your feet. The Gaslamp would seem like a perfect place to have such a thing, but it is not like that. I suspect it is because it is too hard to get a cabaret license. I have heard that story from a lot of bar owners.