At the time I entered UT Austin, in 1986, they had that 10% policy---it's how I got in. Some programs (nursing and business are the two I remember) had competitive admissions, though, but that was for sophomores or juniors.

The University had 50,000 students at that time. During my time there, they were constantly trying to find a way to reduce that number and succeeded at some point, so the 2009 law may have been a result.