There are quite a few devs in Austin, but they aren't all sitting around twiddling their thumbs waiting to start working on your new project.
Chances of ramping up from nothing to a full AAA development team, in one location, in the timescale of a single project, is zero. Not happening. Sure when you first open your studio you'll snap up the people that were unemployed or looking for a move already (but bear in mind these probably aren't the best people), but after that.....experienced devs that fit the myriad roles you need to fill just don't come on the market very often....and they may well have zero interest in working for a studio with no track record of shipping anything.
Opening in multiple cities/countries and outsourcing some development is one of the things they have done right.
1. FPS module was money down the drain.
2. Website spent several years in a mess, it's marginally better now but is still confusing to new players with Spectrum (forums) looking different, having different layout etc. Look at any other games company or in fact any other company - their products have far greater familiarity and are far easier to navigate. Behaviour are a professional company, they have won several awards for their work in recent years - but you've still got to ask why the CIG pages are a confused mess - that's CIG's fault and hiring Behaviour to manage and produce that site is not cheap.
Also Austin had a wealth of devs around the time CIG opened, other companies were in trouble. Foundry 42 was a great idea but Santa Monica in particular was more of a need to be close to home, rather than best for business IMHO and resulted in many veteran devs leaving the company which resulted in a change of direction and a lot of remaking of existing assets, tools and methods. Some of those will clearly be for the best, but the rest is just additional wasted money.