I'm not a martial artist, nor a boxer, nor a wrestler. In two different police academies I've taken very short courses in disarming others.
So you are a highly trained professional with a lot of experience. Good for you! Most of the people present in active shooter situations, ironically, are not highly trained professionals, MMA fighters, don't attend multiples of courses on disarming, open hand, closed hand, edged weapon, handgun, carbine, or shotgun fighting, etc. They are ordinary people. They include a subset of ordinary people who are gun owners and who can legally carry, but for some reason don't carry on a regular basis and don't even usually go to the range more than once or twice a year, if that often.
For some reason, the super fighters don't seem to be present in a timely fashion at these sorts of events with any sort of regularity. That leaves the situation in the hands of the ordinary people.