Because when RAH was requiring pilots w/1500TT, it meant they were poaching pilots from other airlines. Most of the people in my new-hire class in 2007 came from other regionals.

1500TT then meant you got people with 500-1000hrs of 121 experience. Now it means you're getting people with 0 121 exp, but same TT.

That's my bet on RAH's change of heart on 1500hrs