I would not expect BA to pay rackrates at airport hotels. And I do not expect a full load of passengers staying at a hotel. Quite a few will go home and come back the next morning. Nevertheless: It is not relevant whether 140k is "not inexpensive". Obviously it is still cheaper for a carrier to pay 140k for hotel rooms and to fight with a handful of pax about compensation than to keep a sufficient number of aircrafts for situations like this available....

Sorry for getting personal: I am BA Gold mostly for transiting through LHR. BA has been the worst airline for me for missed conncections and the worst airline for rebookings on other carrierers. In 2011 I had four missed connections in LHR. In two instances BA was fully unprepared when I arrived "unexpectetedly" (and even flightconnections was unmanned) late in the evening. In two instances they demanded that I flew from a major German LH hub into LHR allthough it was clear that I (a) would not make a same day connection but could (b) reach my destination in time ex the German airport directly either on LH or even on CX. In all fairness: At the end they paid in three instances, in the fourth one I gave them the benefit of the doubt because of weather related problems.

BA is for me the worst carrier dealing with "unexpected" situations and I only hope that the ECJ makes BA pay for that. If not, we will never see any better but will see an attitude like "we give a room and a meal - what else could you seriously demand?" I demand a simple thing: I expect to be in time in the place I am expected to be according to the contract. And I expect the carrier to do everything that reasonably can be done to get me there. And I do not expect to stay at an airport hotel and waste my time there.