That is a very good point, Puppet, and in nature, the wild dogs are not going to have someone there with a cotton ball to clean out their ears. Most of the wild breeds of dogs, like coyote and foxes, seem to have naturally pointed ears; so they would not gather moisture like a floppy-eared dog does. Even though most of the breeds we have now must have come from some wild breed originally, it is probably our doing that we have dogs without sharp ears. At least I can't think of any wild breeds of floppy-eared dogs, offhand.
One thing that I have observed in dogs, cats, and even horses, is that they will groom each other; so maybe that is how wolves get their ears cleaned ? My Chipper, who is about as far removed from a wild breed as you can get, just loves to lay there and clean Tootsie's face and ears.
I have had cats that groomed not only themselves, but other cats, as well. Also, animals can smell when there is an infection, and will lick that to get rid of the infection, either on themselves, or on another dog. So, I think that wild dogs probably did have clean ears, one way or the other.