I agree that Austin would work, but Houston is so huge and with such a well-established professional sports scene that I have a hard time seriously thinking that Austin would under any circumstance be more inherently attractive than Houston.
Plus, the thing to remember is that Austin already effectively has two major sports teams already, Longhorns football and basketball (not to mention other moneymaking programs like baseball, as Texas is a rare school where multiple programs make money). Like Columbus with the Buckeyes, the local market already has an absurdly enormous college program in town that even recognizing that they'd be the first major pro team in town (intentional slight against the MLS) it wouldn't be accurate to look at it as an untapped market.
I think one of the reasons the NHL went to Columbus vs. Cleveland or Cincinnati is the fact that even with the Buckeyes in town, there was no pro sports competition. No doubt college sports is massive in Columbus and Austin.
Not saying Houston would be a bad market, or that there wouldn't one day be three teams in Texas, but timing is everything and maybe Texas market No. 2 isn't the obvious choice.
Then factor in that live music scene draw bringing tourists in. You get some of the similar benefits that Vegas and Nashville enjoy with a vibrant entertainment scene helping draw people to the area and make travelling there more appealing.
Frankly I'd be a bit concerned with the local Houston economy in the long-term. The Oil and Gas industry is a huge part of their economy what happens if that industry shrinks considerably over the next few decades? If say Austin has a more diverse economy, maybe long-term that is the safer play.
I don't have any numbers but I'd be curious to see the retiree vs. working age demographics of each city. It's the working age folks who generally have more disposable income to spend on pro sports. Then factor in kids interest in pro sports teams can drive ticket sales, merch sales. Not a lot of retirees taking their adult children to pro sporting events or buying pro team merchandise.
Who knows, we've seen markets with huge populations fail, and some smaller markets succeed. And either way, the on-ice product has to be quality. No question one of the many reasons Atlanta and Phoenix failed was absolute lack of on-ice success. Two of the most inept franchises on-ice the past 25 years.