You are only thinking of the visitors centers, where it is not peaceful
(except in the dead of winter). But there is much more to the Canyon
than that. There are countless assessable areas where one will not
encounter another human being in a day. The sound of quiet is amazing,
particularly when combined with the view, and aircraft noise is
unwelcome. When you add up all these places, there are a lot of people
enjoying them.

Peter Duniho wrote:

To me (as I mentioned in a different post), the Grand Canyon is simply not
where you go for "peace and quiet".