It cannot be grounded in reality precisely because it's a monopoly. The whole point of laws against monopolies is to let the market figure out the fair rate, or

It cannot be grounded in reality precisely because it's a monopoly. The whole point of laws against monopolies is to let the market figure out the fair rate, or to define the "fair" rate as the one that emerges in a competitive market. So by definition of what the whole case is about it is impossible to give a fair rate in this case. If you don't want to be subjected to guesswork, stop being a monopoly and let the market figure it out.