I can't see the grass trays lasting too much longer. There were 3 football games played at Reliant this weekend, 2 high school games and a college game. It takes quite a bit of time to change trays in and out, so I assume a majority of that field has been inside Reliant all weekend.
Opening day will look great because the trays in there now will be removed and replaced with the field that's been sitting along Fannin in the sun and rain. But if there's going to be 3 or 4 football games being played there every weekend, that grass is going to start looking pretty bad by mid-season.
Not to mention the labor and upkeep. I drove by a couple of weeks ago and there were 5 18-wheelers having pallets loaded onto them to carry to the stadium. It takes a long time to switch the pallets out. So long that they only had time to swith out the middle strip of the field last year after a college game that was played on Saturday and before the Texans game the following day.