One of the annoying things about Zion was how busy it was in the park and on the walks. We were there mid week, not in school hols and out of the peak tourist season and yet there was still a constant stream of people on both of the walks we went on. The scene above was pretty much the norm.
There were also significant delays on the road into the park. Apparently it is really bad in peak season.
So sad to hear this. The Grand Canyon is probably the worse, and Arches is too. They have discussed limiting the people per day at some of these parks, and also raising the fees for the most popular parks.