Whilst we're on the subject, Gatwick has 18% more movements and 14% more passengers per runway than Heathrow, in it's current state - and Gatwick would have no airspace restrictions with a second runway.
LGW and LHR both have airspace restrictions, you can eye ball LHR inbounds and departures from LGW easily, they're quite close together.
LHR doesn't currently use land and depart on the same runway for any length of time for noise abatement purposes, LGW does and so of course the runway is more heavily utilised.
AMS has been a great option since the Air UK days but in fairness is starting to feel the pinch, it may have six runways BUT as most on here will know, it uses four at any one time and to nothing close to maximum efficiency. AMS is a poor option to connect if I have to go easyJet to KLM, that's two fares rather than a bundled connecting fare for a start, so despite what you say, there's still a few of us who like the T5 ot T2 option at LHR, T4/T3 well, less so
