"Everything is an OLE server" is the closest Microsoft concept. And it is too - files on NTFS filesystems are a lot more than just files, only (nearly) no-one uses all the fancy stuff, and it's not really exposed through Explorer or CMD. You don't really need file extensions, for example, but everyone is so used to them.

The Registry arguably is no more or less sensible than /etc full of cryptically named config files and executable scripts, all in slightly different formats...