Belive me, I'm no supporter of BA, having to work with (against?) them every day. They are their own worst enemy.
However, taking into account runway length, which might have been forgotten here a bit, if BA decided that a route from Stornoway to Hong Kong was profitable...well, great, I've always wanted to see some of the Scottish isles!
It's simple supply and demand. Longhaul to/from the SE of England is where most of the demand is (both outbound and inbound), and there where most of the profit is. Complaining here won't change that, write to your MP and ask that a Hong Kong - Stornoway service should come under ther protected public service route so it will receive a government subsidy.
Is anyone really saying that if UAL and/or AAL went bust, and Continental had the opporutnity to swap to Heathrow, they wouldn't?