The Netherlands also has a nationwide smartcard, making the whole process much simpler. As long as you've touched in, you have a valid ticket. (Admittely, this can be gamed in countries like Denmark, where fines for failing to touch out are around £4 - reasonable for a short journey, but the touched-in card would be valid from Kastrup all the way to Aalborg... You get a limit of these before your card gets barred, but it's still open to abuse.)
Switzerland and Germany do have some stations that are entirely unmanned - but then the rule is that you must actively seek out the guard on boarding. But then, the service will have a guard, and the guard will be in a designated spot, so there's little room for error.
Japan has the right attitude, IMO.
The vast majority of stations are gated. You need a ticket to get in. And you need a ticket to get out. But if you buy the wrong ticket, or you change your plans, no problem - you are perfectly entitled to correct your fare at the exit. There is no assumption of trying to cheat the system, but you won't be able to leave unless you can show you have paid the appropriate fare.
On lines where there are ungated stations, you will pay or show your ticket on exiting the train, which will be through a single set of doors.
The problem in the UK is that we have such a complex fare system. If you buy a ticket in Switzerland, you are buying a single or a return. There's a few other variants, but that's pretty much it. No off-peak, off-peak day, super off-peak, all with different time restrictions depending on where you are, and which journey you've done. In Denmark, you touch in and out - none of this pre-loading your ticket nonsense.
I have no problem going after people avoiding to pay, but there's an awful lot who make genuine mistakes - very easy to do with our overcomplicated fare structure. Should we really go after those people to catch a handful who may try to game the system?