The point of I understand it correctly, is really important. Some on here are saying, we don’t need off peak fares because most people buy an advanced.
If only a minority of people buy an off peak, why do you need to do anything about off peak tickets. Why do you need to remove them. Why is there any problem with them?
Well, yeah, except we know why they want to remove them: they're effectively a price cap on Advances.
I am just calling BS on the idea people don't want flexibility, and responding to a claim that even when people buy a flexible ticket they still stick to their booked itinerary. I'm not doubting that's the case, but if it were a reflection of passengers' preferences (as distinct from being the behaviour the industry has conditioned into them) then you could charge different fares to book different trains based on demand, but you wouldn't need to enforce or even have a rule that they must travel on their booked train, because apparently people don't want to travel on a train they didn't book.
Being a bit more sensible, if you wanted credible demand-based pricing but didn't want to treat people like chumps, subject to availability of seats you could let people change their booking and just pay an excess if they're switching from a quieter to a busier train, and let them do it for free if they're switching between two trains neither of which are busy, or from a busier to a less busy train. You know, rather than penalising people if they help you out by travelling on an empty train rather than the one they booked, which was heaving, as happens currently.
This would be different to the current system where you can change your booking by paying the difference in fare: it wouldn't penalise you if fares generally have gone up since you booked. It would only charge you extra if the train you want to switch to is more in demand than the one you booked originally. So it would be based on comparing the higher of (a) the predicted load factor of your booked train at the time of booking or (b) the predicted load factor of your booked train at the time of the change, against (c) the predicted load factor of the train you want to switch to. And the passenger wouldn't have to understand any of this, they could just access their booking and see a list of trains they could switch to along with details of any excess they would have to pay.
That would be modern flexibility.