The catchment area of London is not enough on its
own to support the amount of BA short/medium/longhaul
flown from Heathrow.
Tourism and connecting account for a good percentage
on top of that and if you can 'funnel' from the regions
then all well and good.
The 'shuttles' operating for BA are very important to the
operation.
People vote with their feet and BA is not exactly 'under
pressure' at the moment.
Why as a private company would you operate out of the regions on long-haul if you can fill the planes from your home base!
The remnants of BA regional are a hang over from the days
of public ownership and as such are being run down very
slowly.
This is not a new idea - just look at all European majors
and their route networks.
BA- Heathrow/Gatwick Lufthansa- Frankfurt
Air France Charlesde/Orly Swiss-Zurich KLM-Amsterdam
Iberia-Madrid Alitalia-Rome.
The fact is that most foreigners want to fly to London and
good luck to them!
MM