I think BE is here to stay though, even though I think it's a terrible way to treat customers on a legacy carrier.
B6 isn't really a legacy carrier... they don't even have lounges, strong frequent flyer program or alliances (just a few partnerships).
Basically, B6 functions as a hybrid airline; they started as low cost and the vast majority of their flights remain single class yet they are adding more and more full-service aspects to longer domestic flights and now transatlantic flights.