I agree with Vont. I started at LGW in 1973 and there were many complaints from commuters and air passengers about the problems of boarding peak hour trains. The other reason the Express came in was pressure from British Caledonian's Adam Thomson who needed to promote a non-stop dedicated link to central London.
The Express has always promoted a 30 minute journey time for
PR reasons despite us locals knowing that the journey time is often more towards 35 mins. Doesn't really matter, does it? It is a comfortable journey (mostly) and I'll pay the extra for the comfort and non-stop service.
I haven't driven in London for 20 years. I always drive to Gatwick and get the train because I know it is four an hour, all night service and non-stop and I can always park. That's what public transport should be.