Well, it's probably not economical for CO to offer 4-5 daily flights on EWR-LHR with widebodies or to offer 2 daily flights on EWR-CDG with widebodies. But it is economical to do so with the 757.

I get the complaints about the IAD routes given their higher likelihood of diversions given distance and what seem to be important routes. However, none of us have seen the yield information on these routes, so we really can't say with any authority whether it was the right decision or not. I would have to guess that their analysis showed the routes would be more profitable with a 757, although the higher-than-expected winter headwinds and fuel diversions may very will have tipped that equation in the other direction. Whether their analysis factored in the "pissed off" element of a handful of FTers, I can't say.