It is surely uncontroversial to say that they must have researched a range of options for how this card would work and how much it would cost a passenger, they put them to potential passengers, and found the predicted uptake and thus the hoped for increase in tourism related economic activity (and thus ultimately return to the Treasury) fell far short of what it would actually cost the Treasury to implement given the potential alternatives. Things which are surely far easier to target and far easier to calculate the cost/benefit.
I strongly suspect it was hard to get around the deep suspicion that the deal savvy British public would rip the pants out of any deal deemed to be overly generous. I know I'm taking the absolute Micheal when it comes to this £2 bus fare, but I also know nobody except the railways are suffering, which in a way, is how it should be. If the railways want my custom, offer a better service than the alternatives. It says a lot that even in these times of supposed deep bus cuts, I'm surprised how far a journey has to be, and how remote the start finish points, before the bus alternative becomes wildly unattractive from either a cost or journey time perspective.
I'm currently planning a cross country trip for purely a one day domestic tourism reason, where the railway can't compete with a £2 bus fare even if this staycation rail card was as cheap as £10 a month, since it might be another month before I am even in a position to take a another day trip, least if all one that can be done by rail.
The railways could of course offer me a stupendously good walk on fare given the route and times I want are basically when they are transporting fresh air across the country and like most British domestic tourists I don't buy a day ticket in advance because the day might turn out to be a washout, but they won't. It seems quite sad that I no longer even know if the reason they won't is because of a lack of commercial imagination or the stifling dead hand of government bureaucracy.