Speaking as an SD native, and a 25 year old developer, I've definitely felt the urge to move to San Francisco at times, but I could totally see SD becoming a huge hub for the tech industry if given the chance. SD would need some huge transit changes (it would be great if it actually worked), and having companies move downtown would relieve a lot of the hassle of commuting.

The north county areas of SD, where the tech jobs are, feel a lot like Silicon Valley, and I don't think that's a good thing. Leaving Mira Mesa for SV is not a win in my book. SF proper is an amazing place, much like SD, with lots of culture and stuff to do, but unlike SF, SD doesn't have the clout with the tech culture. Personally, I'm always excited when people say they're creating tech startups here, and I hope more people do.

Plus we're always on vacation here :P

EDIT: I agree that most people I meet are not interested in working for Intuit and Qualcomm.