Jobsa - Understand completely what your saying re dominant airlines, however I cant agree with your statement re BA at BRS, if they were to go they would have gone a few years ago when CWL/LBA went, BA in the face of an on slaught from EZY have weathered the storm well and come out smelling of roses if you ask me, they've added routes in the past year such as ZRH, MXP and a new route of DUS starting soon, plus they have the ground contracts for SN,WOW and Eastern, so I find it hard to believe that BA would be pushed very easily from BRS, they still compete with EZY on routes such as GLA/EDI and have the upper business market who do not wish to fly with BA, Sorry i know this is an EXT thread so i'll leave my rambling to that.
Fact to me remains that as i said earlier until EXT has better facilities it will not attract another based carrier, i mean even the terminal is painted inside in flybe colours!