I take it you've never been to an airport then?Or to a bus station in a busy town centre? And, away from public transport, how many petrol stations are that don't have an accompanying shop?
More seriously, I doubt anyone is suggesting that rural stations that see little use should have really elaborate facilities, but I think there is a case for many stations to have better than they currently have. And, although I can't quote any figures, I certainly recall reading that there is a fair bit of evidence that improving station facilities and the station environment does often increase passenger numbers. Maybe other people here will have more specific information.
Westbury, which can get quite busy at certain times of day, used to make do with a cramped waiting room and a tiny kiosk serving tea in polystyrene cups for years. This has now gone, replaced by a bigger (franchised) tea/coffee kiosk in a bigger waiting room. Quality has slipped a bit, but quantity has increased (whether that is a good thing I don't know).
With petrol stations, they obviously sell petrol, so anything else would be a sideline. And bus stations usually are not as isolated as some railway stations. They tend to be in the middle of town or adjacent to big shopping centres, so the situation is a bit different, like counting the Howard Centre as being associated with Welwyn Garden City station (although I suppose the siting was suggested by the station).
