There is a widespread approach in sci-fi/fantasy franchises to use alternate timelines/parallel universes as a technique/device to continue/extend/expand the franchise. Notable examples I can think of include Superman, Star Trek, SG1.
I know that some fans like me who appreciate a well built fictional universe, specifically for its continuity, find the abuse of such device to be problematic - they may appreciate an odd SG1 episode dealing with parallel Universe, but would not necessarily be interested on a whole series based on it (like the new Star Trek movie seems to be ushering in). I'd be curious as to whether such attitudes are odd or common. Therefore...
Is there any evidence (popularity/ratings/average, user-reviews/revenues/scientific surveys) to indicate whether using such a device increases or decreases or doesn't affect the success of a franchise?
I'm interested in (preferably systematic) evidence, not personal opinion.