Maybe if the guards got a commission for selling tickets? Do they anyway??
Get on a train in Gtr. Manchester from an unstaffed station without a machine, wanting a Gtr. Manchester evening return, if the guard doesn't come round selling one, and you get off at an unstaffed station, you face paying double to return home. Hence banging down guard's doors on occasion.
No matter how many times I've read arguments against on here - let's have a machine on trains that lets you buy a ticket; and one that sells the right one too - unlike Bolton Trinity St. which the machine won't sell you (cheap) evening returns. the bloke on the counter KNOWS it doesn't, so the unwary will be forced to pay the full fare (not much, I know, but many a time there's a group on a night out) and there's not even a notice saying the GMER is available at the counter - and what he thinks of the operators for doing that isn't printable.