Yeah because I want to haul all my luggage on a train journey when I go to the airport. I’ll take a train to a lot of places but the airport is not one of them.
My company pays for taxi from my door to the airport and I still take the train, unless I am leaving before dawn.
There is both a rational environment choice in that, and a nice feeling of being part of a humming crowd
Presumably, you've never taken the Heathrow Express? That is a train journey that is always better than a car. The Gatwick Express, not so much.
Doesn't have to be binary. Train is more efficient at moving large volume of people reliably compared to a bus or a taxi. I would wager that there are many more people travelling with carry-on only or a single bag for which train is more than adequate.
I travel 40-50 times a year by flight and I absolutely don't mind taking the train. I live in Zürich which has an excellent rail network.
Easier to haul my luggage on a train designed for that purpose than take a car and spend longer parking it than the entire train journey. I live 10 minutes from Gatwick, have never driven there, and don’t understand why anyone would want to if there’s any alternative.
Taxis I understand.