Comment by dragonwriter

That's not the doctrine.

The doctrine is that you can't exercise monopoly power in certain ways. Monopoly power is an empirical question, and does not turn on merely whether it is possible to describe a market in which another product exists, but whether that is a real market in which the products are in fact competitive.

But even if you have monopoly power, if you aren't illegally exercising it, you aren't in trouble. So you aren't punished for being an empirical monopoly.