or has the author thought about all the jobs that would be lost....
Doh.
If Heathrow is closed (as it would be if a Thames Estuary airport were ever built), then jobs would be lost whether it was turned into a garden city, a theme park, or frozen in aspic as a monument to 70 years of UK aviation policy.
If it's the closure scenario that you have a problem with, that's a completely different issue. Debate that sensibly, by all means, but the author's proposals for the aftermath have no bearing on it.