It's something but the CR needs much more than just cheaper monthly passes. There are too many zones, some stations (such as Lynn or the Brockton stops) should probably be moved to nearer fare zones for equity, individual fares obviously need to be cut too, and some zones should possibly have their fares cut by more than 1/2 (Such as Zones 1/2) while other zones (~7-10ish) probably don't need the full 1/2 cut. Using single fares for an example, I don't think a fare of $10 to get to Providence is necessarily unfair, for example.
Temporary Summer thing perhaps? When I looked into it, the cost was 16-16.5 roundtrips per month, if you don't use the subway at all. Dunno what the % stay home on Fridays, but it's probably high. Throw in a vacation or two and you could see why people drop the pass during the Summer. And if you say allowed free subway transfer, you'd have to include those people too.
When talking about cheaper fares overall, also have to consider the loss per rider (versus say bus or subway)