The single ticket pricing strategy (whereby halving the price of a return) makes little sense since most people lose out, bar the single travellers. It reinforces the preposterous idea that very few make in-and-out journeys on the same day.
If a return cost £100 and now two singles cost £50 each, how does anyone lose out?
In fact, given that most people know at least one departure time, they can often take advantage of an advanced ticket in one direction and so can see some advantage whilst still being flexible with the other.
The 70 minute tickets which LNER have just launched (allows you to swap to any train 70 minutes either side of the original train for free or any train for £10 admin plus any uplift in ticket price) aim to tap into this, in that most people could be sure of when they are almost certainly going to be travelling within a 140 minute window.
To give a practice example, I used to have a team meeting in a location with an hourly train service, the meeting was at 9:00, with the return services running at xx:30, there's no point being on the 9:30 or the 10:30 as the meeting would be longer than that, there was a slim chance that I would be on 11:30, but could have needed to stay to leave in the 13:30, so as long as i was booked on the 12:30 i could flex the ticket to suit.
I knew which service I would be on for the trip up (it was the first service of the day that I could actually catch), so could always book that as an advanced, but then had to buy an off peak single.