Naturally, I know that prices vary, that is why I asked if I was just having a bad day. Your interpretation above may be more accurate, given your own experiences.

I wouldn't complain about the phenomenon (price fixing is generally not good), but the fact that the "decoupling" occurs is interesting in iteself. No matching implies that either (a) the airlines assume that people have some other reason, e.g. connections/loyalty, to fly the airline, or (b) they don't see that they'll lose much revenue through people walking to the lower cost carrier.

I guess this would make building a MR more difficult if you live in a hub city for the designated airline.