I think the problem is that the feedback loop between UTCS and the Austin startup community hasn't hit a critical level. I can't name a single product made by an Austin startup that I've used, while I can think of dozens within a few miles of Stanford. Additionally, plenty of SV startups are within walking distance of Stanford, whereas most Austin startups are at least 10 minutes (by car) from the UT campus and are located in office parks, rather than the open pedestrian environments of University Ave and Castro.