BA's adapting now. Just like mother nature... ;-)
Recent experiment in France : Air France is adapting as well. They're selling cheaper and cheaper tickets. On par with now-dead Airlib low-cost airline and with the TGV train.
At relatively same prices, I would now consider hassle, prices of transfer from airport, onboard services...And would probably choose majors.
Or in France, I would simply go for the TGV which is an absolutely wonderful tool !!! less than 3 hours for Paris-Marseille, city-centre to city-centre, no check-in hassle, no endless security checks, quiet, nice restaurant, no extra expenses to get to and leave from the airport...
It's going to be a very tough task for ALL airlines, to fight the TGV in France especially considering the SNCF's expansion plans...