Surely the key (and the profit) is interlining with their extensive European network?
One of the principles of LCC is that they don't interline, for many reasons. I can't seem the moving in that direction, because if they did they would then have to charge the higher fares that interlining entails, and would thus lose their only competitive advantage, that of perceived value.
Apparently they have announced that they are looking at distribution via GDS channels (EZY have been doing so for a while), which would be another significant departure from the traditional LCC model. They would of course screw the segment fees down to the last fraction of a cent, and I feel sorry for any GDS account manager who has to deal with them.