But what you're saying is that eventually you'll make money on every transaction which just goes along with the comment made before. The joke is really about goods where you can't lower the cost or increase the price enough to make the economics work.
> The fist copy of Microsoft Windows might cost 1 billion dollars to produce, while every next copy is essentially free
You'd have to split R&D costs by the units sold here. If you spend 1B and sell 1000 copies a price of 100$ per copy won't help you.
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.
> The fist copy of Microsoft Windows might cost 1 billion dollars to produce, while every next copy is essentially free
You'd have to split R&D costs by the units sold here. If you spend 1B and sell 1000 copies a price of 100$ per copy won't help you.