And lots more don’t. The difference is so large that the ones who do offer commercial support are a rounding error in comparison.

> And the truly free-as-in-beer projects either have some kind of grant financing or else the maintainer shoulders the costs until they burn out.

Those aren’t the only options, that is a false dichotomy. But even if it were true, it in no way contradicts the argument.

> That "nice slogan" is emphatically true.

It emphatically is not, and you are ignoring half the argument. You can pay and still be the product.