Yes...when one considers long periods of time, it seems that there are probably an infinite number of scenarios as to how we got our moon.

Also, I think that analysis of moon rocks suggests that the moon is not composed of debris from the earth (when inferring from elemental composition).

Maybe there's a not too well understood process which "attracts" asteroids to near the earth. Over time...the earth just accumulated the captured asteroids into one lump called the "moon". Other asteriods impacting this clump of asteroids may have shaped the "moon" into it's compact version as seen today.

Sometimes moon related info. sheds light on earth matters too....