Ever notice how the label area, and the lead in groove area are raised above the playing surface of an LP? This is so when you stack them, the playing area isn't touching that of the records above and below. Not every record is made this way, but a majority of them are.
The main wear related issues with changes in my view, are the often elevated tracking force, and the fact that it's hard to have a good record cleaning regime with a changer. I like to give each side I play a quick pass with a carbon fiber brush before it plays, and I have no idea how to do it on a changer.