Hi, my bad for replying an old message, but it's just to share an educated observation, you say that had you never started shaving you wouldn't have such dominant and strong mustache, but that falls in the same casistic mentioned by the commenter abve you, growing up and puberty, of course, like many more or less start shaving when the facial hair becomes annoyingly visible but still in the fluffy phase, then continuing the same process which led it to become this visible and the aesthetical, perceived or not need to shave, it keeps becoming more robust, like it would have done anyway. It's the same reason chest hair which many or most don't shave, especially in past (completely legit preference either way), becomes first visible, then more robust, same for leg hair.

The shaved hair is just more blunt, but it actually got more robust and thicker for unrelated reason in such case.