Left to its own devices, I think the river would reclaim the area and it would become a delicate ecosystem again. OTOH, all the people moving to Austin have to live somewhere, we don't want them all over the Edwards aquifer recharge zone, and this bypasses gentrification.
Austin ranks 10th among the top 50 U.S. metros, adding 18,500 jobs (1.4% growth) in the year ending May 2025.