Whatever has been said, this sums up the whole argument:
Just booked flights to NYC, could have saved £100 by going via LHR, but why run the risk? Friends did that last month and whilst they got to New York, their bags didn't. That happened to me the last time I used LHR long-haul, bags didn't make the shuttle flight back to MAN after flying all around the globe.
Some people would agree with you spending the extra £100 on your flight and 30 odd million do not. If you have had a bad experience with BA then I would probably do the same as you within reason.
At the end of the day people decide which airport they wish to fly from/to/via by their own experiences, price and suitability. Not because over years BA have pulled out of an airport and focused on the capital.