Here's how I eventually got the hard-core non-updating windows 10 machines back to normal.
- Log in as a local administrator
- Stop Windows Update and Background Intelligent Transfer services
- Clear out c:\windows\softwaredistribution\
- Clear out c:\windows\system32\grouppolicy
- gpupdate /force
In SOME cases, the Windows 10 Update Assistant would at least bump up the current patch level, in some cases not.