I think the average AEW fan also watches WWE, where the opposite is not true to nearly the same degree. If they have the time, they can watch both.
If you factor in the opportunity cost of doing something else instead of watching wrestling in a given week, those fans have to make a choice about which show they will drop to do something else, like going out or playing video games.
AEW is not only competing with WWE but also with all the other things a fan may want to do in a week.