this year, given the season it's having. Of course, it plays its home games 90 miles away, so that isn't a Boston attendance issue. NESN still covers a fair number of HE games, as well. Merrimack is probably not a good example, in part because it's never had a consistently good program and because its rink is tiny. I just don't think that your correct generalization about pro vs. college fits the hockey niche. In other words, the recent falloff is likely due to something else.
NESN seems to have some individual deals with teams.