The age of Windows 10 isn't really the defining factor. People didn't buy their computers on the day Windows 10 released.
The age of Windows 11 is what's important. When was it actually possible to buy a new computer that came with the newest version of Windows? Anyone who bought their current computer a day before that date (and quite possibly some months after) are being told to trash machines that are only about three and a half years old.
The amount of electronic waste being generated by this is obscene.