I expect the advertising comes out of the fact that Windows 10 is Microsoft's first proper attempt at a free upgrade. But yes, people have paid for Windows, so

I expect the advertising comes out of the fact that Windows 10 is Microsoft's first proper attempt at a free upgrade. But yes, people have paid for Windows, so in this case it's unacceptable — but I don't think Microsoft figured out (or particularly cares to figure out) what installation is what type.