Paxboy
I agree with most of what you and S1E say.
But Lhr has taken the 9 steps you give above, where do they go from here? I believe that even if Lhr gets the green light, it could be 15 years before that new runway is operating, am I right? Let us assume that demand keeps on rising, even with some shocks. Those carriers at Lhr need to and want to add services. Now they have decisions to make. At some point the three costs you state will become uneconomic, even at Lhr. It might take them a while to figure that out, due to ego, but it will happen. So what do they do then?
1. Pay those ever increasing costs at Lhr, even as their services are made loss making/much reduced profit because of the costs
2. Forget about the rising demand and leave to others, who may be using Lgw already
3. Start at Lgw.
I know where I would place my bet.
It is slightly different for Ba, they can move services to Lgw to free up slots at Lhr, but foreign based carriers have no such option. I also believe that the change of owners has made a massive difference at Lgw. BAA had no interest at all in promoting Lgw, GIP are a different animal.
Re the airlines you mention who tried Lgw and quickly moved to Lhr. I would question how they could decide on the future of a route after one season. Air China has stated they could fill 4 flights a day ex London if they could get the slots. If that claim is true, is it not odd they could not make one flight a day ex Lgw work? How long did Korean try? But look at Turkish, fairly recent to Lgw and I believe would like to have five services a day next year. Icelandair, going up to 8 a week later this year I believe. I look at some of these carriers who moved quickly to Lhr and I ask myself, did they really want their Lgw service to succeed at all?
At the end of the day, it is only when we look back in maybe 10/15 years time that we will see who was right. In the meantime, a great debate and a lot to play for for both airports and the country.