[ergothus]

You are of course correct in your math, but the point is that it reverses the equation. Windows doesn't cheaper to make if you plan to sell fewer copies: the production cost is set (Roughly) so you have to target volume.

Then you have the secondary effects of lock in (with software/services) that makes every sale also reduce the cost of a future sale or economies of scale (physical goods) that again make volume more desirable.

This doesn't contradict the adage about having to sell at a per unit profit, but it complicates figuring out what number that is and can lead to some non-intuitive results, which does trash the value of the adage as a simple way of looking at things.

Not saying every company that is selling at a loss to get customers in hopes that they'll mysteriously figure out how to later profit is doing so correctly, but some are. Oversimplification adds little value to these problems.