It's crazy easy to find warezed copies of Windows 10 on U.S. Amazon ($12 for somebody to burn a DVD of their bittorrent download, $15 to add a key).

By contrast, searches on AliExpress for Windows OS in any form dead-end hard. And it's not for lack of consumer interest either; Enter "Windows" and autocomplete suggests all possible combinations of "Windows", "10", "7", "OEM", "Key", etc.

I hadn't spent too long at this because it was out of idle curiosity rather than desire. YMMV.