why the heck would anyone not learn theory?
the only professional drummer i know who doesn't know how to read a single note is Dennis Chambers, and that's only because he memorizes every single thing that he has to play. Whenever musicians hire him he'll have to memorize large chunks. If you can do that, then more power to you.
If you noticed, his playing has not changed a single bit within the last ten years. I believe it severely impairs him, but he's at a level good enough to not care about this issue.