At a guess: you pay for Windows and MacOS (or whatever they call that now). And because they need you to pay, they bring out a new version with a Fresh Look, C

At a guess: you pay for Windows and MacOS (or whatever they call that now). And because they need you to pay, they bring out a new version with a Fresh Look, Clean, Modern, New And Better (until they come out with a Newer And Betterer version). That said, this doesn't explain new versions of Gnome, etc., nor why updating from Windows 7 to 10 was free.