In the past there has been rival leagues when there are cities who have interest in hockey and do not have a club. Cities like Quebec or Hamilton obviously. But cases have been brought to the NHL for Saskatoon, a 2nd Toronto team, Kansas City, Vegas, Houston, Seattle...
None of these have happened but there are cities wanting teams... that has created at least one rival league in the past.
I mentioned above that I don't think that there is enough people with mullah to get that started... but if history repeats itself we could see something.
(more of a devil's advocate bit tbh)