Look at Worcester. After the Ice Cats (AHL) left they could have had an ECHL team but decided to continue to try to get an AHL team and they did.
There was a reason why that ECHL offer for Worcester was refused. There are already seven other AHL locations in New England. Worcester is in the center of it all. The closest ECHL location from Worcester was, IIRC, Atlantic City (before they moved to Cali). It would be bad business if the ECHL came to Worcester because of both travel costs, and how the "EC" is a lower level than the "A." That would be the same issue if the ECHL came to Lowell.