What Trump didn't do is only because he was unable to do it, for obvious reasons. Just because people say he has the legal authority to do this and that doesn't mean the system isn't rigged to make it nearly impossible for him to use that authority. Remember Mark Esper when Trump wanted to use the military to stop the riots?

Even if it's just optics, you can clearly see now that bad enough optics gives options to guys like Pence to use the 25th, apparently. Which is why he said highly uncharacteristic things in his last video (unless that was actually a deepfake).