After I got out of radio, I worked in the concert industry for several years.
Promoters (and everyone else involved) have really been pushing their luck with these temporary stages for the last decade. Artists are demanding more and more stuff to be hung off of these structures. It doesn't take a lot to blow these things over.
Folks have just been lucky that no one has been killed up until now.
The "smart" thing to do is to get the roof lowered as quickly as you can. But the way that PA, video, and various other set pieces are hung now, it really hampers being able to do that. At a bare minimum, you release the tarp over the roof and take the water damage. But promoters aren't willing to do that, betting that it will the storm will "blow over".
Maybe now, when the promoter/artist asks for "just one more video screen" to be hung (which can be 2 to 4 tons), somebody will step in and say "NO".
Cheap Trick (who were caught up in a stage collapse in Canada recently) have stated they will not perform on another outdoor stage by the same manufacturer.
You can engineer those things only so far. But putting up a temporary structure that weighs 100,000 pounds, and then hanging another 60,000 pounds off of it...it's just not going to survive winds much over 40 MPH without getting the roof lowered.