Though not directly involved or in the know, I live close enough to Houston to see the updates on the news... Apparently, Houston ISD has been mismanaged and underperforming for a number of years with no/little noticeable improvement and so Momma has counted to three and told HISD to go get the belt.
My wife is an elementary teacher (Teacher of the Year!) in the greater Houston area... She's told me the threat of state takeover applies to all districts.. If you perpetually underperform/mismanage, there will be consequences.