Historically, LHR has held a certain magic - just as JFK and CDG, or any other capital city with more than one airport. So, folks like Continental wanted to get to LHR to be at 'the top table' and be able to brag about it. They say it's about their customers and choice, but it's actually about bragging on the golf course.
Unfortunately for CO and others, LHR is now a busted flush and no possibility of climbing back up the ladder. They should have stayed at LGW and boasted about what they could do there with less congestion and competition. It will be interesting to see how long they stay at LHR.