with or without your railcard? I am NOT trying to be difficult but the discount is reducing the profitability - I maintain: if not at least breaking even bin FC OR make it pay.
To be honest the railcard doesn't matter, there is an amount for a journey at which I will say no, then one of 3 things happen, travel standard class, use a different mode of transport, or dont make the journey.
If the amount I pay is profitable to the operator, which in the case of Hull Trains (a large proportion of my UK first class journeys) as an open access operator its likely to be then thats fine. If the ticket price goes up beyond my price point then something will change. HT must factor a proportion of railcard discounts into their calculations. Because its an advance ticket, bought direct from HT I assume the revenue goes straight to them rather than into a pot to be distributed as would be the case with an open ticket.
A large number of routes are subsidised by the taxpayer, how do you manage that subsidy wrt to first class, are you expecting the first class traveller to pay the full commercial cost of the journey whilst standard class is subsidised, or is it a subsidy per passenger mile, in which case first class pays for the extra space and any 'freebies'.
And if people decide to use another mode or not travel if first class is either unavailable or too expensive then thats revenue lost unless the train is at 100% capacity, in which case its only really the marginal costs of providing first class that should be added to a standard class fare.
At a simple level the uplift has been around 50% for a lot of journeys for many years, and that feels about right in my mind. I know there are outliers, both for more and less, but they are usually where some other effect is making a difference.
Interestingly in France its often possible to pick 'prem' tickets up for first class for a few euros more than the standard class, but of course there are no freebies, its just a nicer seat.