It's economies of scale reversed, normally you'd expect the price for everybody to go down over time, not up.

Wonder what the way is that is justified to the end users.

In order to arrive at economies of scale, you have to first provide for the expenses of ramp-up. So far, admission is nominal for the value its payers perceive. Plotting growth against current cost should give a pretty good forecast of how much is too much. Of course, under the current special circumstances, we could even see a freeze.

The price should begin to reduce itself with a function of rate of signups.