You are not a pilot are you - certainly not one who has been into LGW regularly. Hek, man, you cannot get a sheet of paper between the inbounds and outbounds at LGW sometimes.
Bollocks as ever, outwith peak times there are more than a few gaps. Even in peak summer the airport is clearly half empty at times, I have arrrived many times into a deserted South Terminal. It's not narly as capacity constricted as you make out.
And mark my words, if Silver-Boris was being constructed, and LHR had been earmarked as a technology park, B.A. and all the other majors would be gleefully making plans to relocate to the Thames.
Only by being forcibly evicted at substantial cost as you well know. Keep taking the Kool Aid. BA have stated repeatedly they have no interest in your fantasy.
Let's list the commercial supporters :
1) Nobody
2) Nobody else
3) Disregard this and keep dreaming...------------------------------------------------------------------------------------------------