Hehe. I hope you guys realize we can see these threads as well...
Paul, don't take it personally. I don't hate Texas. If someone had said the same thing about Detroit and Toledo, I would have been just as adamently against it. While I guess it's possible that at some future time the two could technically form a CSA, I just don't see any evidence for it happening now or in the next few decades. Also, I don't think the leaders in either city are ignorant in general. (They must be doing something right if tens of thousands of people are moving in ever year.) However, they certainly are ignorant to what the OMB does and how CSAs are defined.
Like I said before, there's nothing stopping the two regions from cooperating as a single mega-region of 4 million people. They can plan, coordinate, and develop in unison and connect the two cities with a commuter rail line. They can even market and refer to themselves as the San Antonio-Austin area to prospective businesses, residents, developers, etc. However, one thing that none of us will see any time soon is a list on the Census Bureau's website that contains the phrase "San Antonio-Austin CSA". You obviously don't have to take my word for it, but I certainly wouldn't hold my breath, if I were you.