They can still codeshare on BA’s Irish routes (LHR-DUB/BHD), they can make money without the costs of operating the routes, plus they can make further money (a lot at current rates) by selling the LHR slots in the first place
Remember also that BA is not “competition” for EI, but a relativity close partner for quite some time now
The bigger question here is that there is simply that there is there is a lack of space at LHR, this is hampering the BA + VS/LHR/London/England/UK from competing with its rivals and contributing to the economy,
What kind of BA agenda are you pushing here? Don't you realise how ridiculous you sound?
If EI are operating the flights, and not BA, then they're the one's making the profit, why would they give away a profit making route to BA?
Also, the fact that BA can't expand from LHR to compete with the likes of EK, EY and TK is absolutely none of EI's concern, they don't owe BA these slots out of sheer good will. What in gods name makes you think that EI would give away it's biggest route to the competition, just so that their competition can compete better? That's just nonsense and makes absolutely no sense on the part of EI.