It is. In most smaller cities in the US, calling a cab means waiting 45 mins for it to show up. The SXSW crowd doesn't have the patience for that.

And you're right about Austin's growing pains: the taxi shortage is very real even on a normal weekend. But Texans are also some of the friendliest people you'll find; which is a big part of why people love Austin enough to cause those growing pains.