Well I'm a single user not on a corporate network, but I can see that the
windowsdefender.adm file is listed in the directory C:\WINDOWS\inf folder,
although all active ADM files appear to be located in
C:\WINDOWS\system32\GroupPolicy\Adm... so how it should be installed/moved
over there is beyond my Home Office knowledge, sorry.
As to your second question about paying for it, since it really doesn't
seem so strange to me that they (MS) want payment for providing
subscription protection to a corporate environment, while keeping
individual users protected for no charge above what they originally paid
for the OS software. It's a rather common practice isn't it? I can think
of many other third party security products that use this as a marketing
technique, that is giving it away to individuals but renting the enterprise
version. I'm not defending the practice, I'm just curious as to why you're
surprised by it.