But if the trains are currently running around close to empty during the day, then surely it is better to offer 50% fares and fill them?
I'm not sure it is entirely the case that trains are running around close to empty.
Here in London I'd say LU trains are now running around with what look quite close to normal off-peak loadings (bear in mind LU is now running pretty much a normal timetable), perhaps just slightly down which I'd say is probably accounted for by the lack of foreign tourists in London at the moment.
Suburban routes which are traditionally busy (like Liverpool Street to Shenfield or the North London Line) are also back to reasonable loadings, whilst traditionally quiet routes like Tattenham Corner I'd imagine are as quiet off-peak as they always were.
There's also some quite significant day-trip flows, sources tell me there's been 12-car Thameslink trains to Brighton running with standees at certain times.
What we don't have currently is the commuter peaks which multiply demand by a large factor. I don't think offering deals for off-peak use will make a jot of difference to this, and in many cases off-peak leisure use has likely already recovered - those people who feel comfortable using trains will already be doing so. In any case, with the schools going back there is likely going to be a reduction in day-trip use from next week, and a cheap deal isn't going to make much difference to this as kids being at school means a family day out simply isn't an option.
Then there's masks. I've sort of drifted to using the car for work journeys at the moment as I simply can't be bothered with the whole masks thing. Fortunately I do not travel at traditional peak times so there's unlikely to come a point where train returns to being the more expedient option. I'd love to be using trains to get to work, and would be doing so were it not for nonsense like the masks thing. One is rarely alone, so I'd bet I'm by no means the only one.
As I said elsewhere, silly schemes aren't IMO the answer to all this. We desperately need to have a "get the masses safely back to work" campaign. That would resolve many issues at a stroke.
In fact, wouldn't some kind of special offer on season tickets be more valuable in enticing people back? Perhaps also the industry will need to have a re-think on quality -- no doubt one factor in the post-1990s demand increase was privatisation bringing enhancements in the quality of rolling stock, unlike some of the 2010s stock which has been distinctly austere. Something like standard class on a 700 isn't really that enticing, it might cut it as a distress purchase, but not if the industry now needs to reach out.