My thesis: Central Austin has a strikingly low percentage of families compared to the suburbs. None of the usual explanations applies -- i.e., central Austin families (except for those in a few neighborhoods) have not abandoned central Austin because of crime, overcrowding, post-industrial blight, bad schools, or the flight of jobs to the suburbs. The only explanation, I think, is that Austin's suburbs have better, bigger and cheaper housing.
I did not offer a prescription. Anyone who reads this blog can guess, though. We need more multi-family in central Austin to relieve the price pressure on single-family homes and to give households more options. (Multi-family has many other benefits besides these, of course.) And we need to make it easier to upgrade central Austin's generally older, smaller and inferior housing stock. The McMansion ordinance did not cause this divide, but it certainly won't help. (For those who don't know, the McMansion ordinance bans even relatively modest homes on some lots, homes no one would call a McMansion.)
I often experience buyer's remorse after writing a piece like this because I'm afraid my single friends will take it the wrong way. I don't think families with children are more important or "better" than other households. I merely think Austin's core must have a good mix of households to remain healthy. (The suburbs would be healthier, too, if they offered singles or couples something other than inexpensive housing in compartmentalized pods.) Balance matters, if for no reason other than allowing us to continue using the expensive assets (like schools) already in place. I don't think we have a good balance now.
For those interested, here is my previous piece at Newgeography.