There aren’t many $1.5M houses in Austin. In Round Rock (home of Dell), the highest price you’ll find is around $800k for a 5600 square ft house with premium upgrades.
Most of those are well over $2M. 1.5M is a tough price point here, because the ones by the water (most of the ones in your link) are really expensive while just a few blocks away the price drops quickly.
Property tax bill on a $2.7m house in SF is ~$32,400/yr, and the property tax bill on a $1.5m house in Austin would be around ~$33,000/yr.