Microsoft uses games partly for educational purposes: for example, Solitaire taught a generation to use the mouse to drag-and-drop. With Windows 8 and 10, Microsoft moved the games to the Windows Store. This should have taught users to log on and download them.
These Microsoft games are still free, but they now include adverts. This is almost always the case with free store-based apps whether on Windows, Android or Apple’s iOS. Companies don’t charge for the games, but they charge to remove advertisements or to add extra features. That’s what happens when people don’t want to pay for content.