I'll have to bow to your experience in the sector as you know it more than any of us, but would the creation of one airport in the Thames Estuary really close Heathrow, Gatwick and Stansted??? I just can't see that myself. I think those airports would probably drop to 60-70% capacity, while the new airport took up the slack.
I can only see the demand for air travel growing and growing over the next 25yrs. We've got these emerging markets opening up, and yet I read in a report about a month back that hardly any of our airports have slots allocated to get connections to them, as the focus is on transatlantic travel.
The compass is constantly changing though, yet the SE airports apparently don't have the capacity to react quick enough. The way I see it, I think Stansted will continue to grow as a the 'go-to' airport for domestic and european shorthaul; Gatwick will probably get busier with international flights as Heathrow continues to burst at the seams.
I know what you're saying about the idea of there being one big workforce, but I just don't think logistically that will ever be a go-er. It's busy and difficult enough at the best of times - forget summer - to get into the current SE airports; I just cannot see how the government would sanction all of those people congregating on one place. fudge me, the amount of extra motorway and infrastructure you'd need to build to support that would be astronomical. And then you'd have the noise complaints; it's hard enough to spread that across 3 airports, how could you ever get away with focus all of that traffic over one area!?
Any suggestion of amalgamating all SE airports into one megahub - in my opinion - would be categorically dismissed. I just cannot see how it would ever be allowed to happen. Even if the airport operators or airlines wanted that, the passengers - the customers who actually pass through it - just wouldn't stand for having to migrate across London to one airport. No chance. At the moment I think it works fairly well how there's a fairly major airport on at least three points of the compass (that being around London) No way the public would accept that relative ease of access being taken away from them.