They probably want to hold off as long as possible on a BOS airbus base (because of all the training events it will create),until they get a handle on the training backlog. They are supposedly going to get LGA airbus pilots International qualed in the coming year. It would not surprise me to see them use other bases to cover BOS international, a la how DAL does it. Or just DH us up there like we already do
for some long haul routes around the system.