A large foreign carrier at Paris was once invited to speak at a French government consultation conference about building a 3rd Paris airport - to add to CDG and Orly. This sole foreign airline representative told the conference that it didn't want a 3rd Paris airport, and ideally would have preferred not to have a 2nd. The reasons were that an airline would potentially have to split its resources yet again, implying impacts on schedule, passenger catchment overlap, connections, engineering, staffing, customer communication and critical mass generally.
For BA, developing LCY must have been an expensive exercise due to 'cannibalisation' i.e. all the LCY costs were incurred, whereas BA could have got say 30-40% of the revenue anyway through its existing flights at LHR and LGW. My point is that margins must have been challenging, just as Mr Walsh now states. He's not bluffing.
The Paris speech delivered in flawless French was received enthusiastically by the French airlines present. They were perhaps reluctant to say the same thing so directly to their own government.

Hmmm.... a big plot of land in central London, I wonder what else could be on the mind of potential buyers!