I think moving away from supporting really low end hardware is a reason as well. They're ditching 32-bit processors entirely, so no need for a separate Windows

I think moving away from supporting really low end hardware is a reason as well. They're ditching 32-bit processors entirely, so no need for a separate Windows 32-bit anymore. Dropped support for less than 4GB of RAM (which Windows runs badly on). Dropped support for sub 720p displays, which most software won't work properly on anyway. Etc