> Why? Windows 7 gets regular updates. Windows 8/8.1/10 are not updates to Windows 7, it is a different operating system

I'll address this point, the sibling comment already addressed the other point (it wasn't meant as a criticism, by the way).

It's true that Windows 7 still get updates. However, these are mostly security updates, or bugfixes. We don't expect it to get new features. In this case, unicode font rendering. It is likely (but not guaranteed) that a user running Windows 10 would see a much better result.