If we go back to the beginning of the season, after the Casey DeSmith trade, Hughes mentioned that he would like to trade another goalie before Christmas. We know the outcome, with several teams inquiring but none making an offer worth mentioning.
We know that the Maple Leafs offered a 6th-round pick for Allen, and other teams offered a 7th-round pick. Clearly, it's not what the Canadiens' general manager wants, and he is willing to be patient.
This means that the plan has changed, and the organization has now come to terms with keeping three goalies for the entire season. Obviously, this happens when none of the three has been injured.
Kent Hughes seems very demanding, and he won't deviate from his expectations. He clearly prefers to keep the situation as it is, even if it's problematic, rather than addressing it by accepting a bit less in return.