A lot of nonsense and unfounded speculation in this discussion!
However one supposed fact about the Ryanair vs bmibaby Belfast saga is that Ryanair pulled out of Belfast in a typical toys out of the pram dispute with the airport over the proposed runway extension. Not because they weren't making money on the route - which would indicate there's no reason why the route can't be profitable for bmibaby.
That is of course if that was the real reason and not an excuse to get out without losing face. BAA airport fees are good for that....