Just about all the results there appear to be abandoned cPanel placeholders and similar — very few even have domains. I couldn't look at all of them, obviously, but this seems to bear out the idea that nothing anyone cares about is run on PHP-CGI.

The headers suggest ancient, unmaintained systems running outdated, no longer supported software with multiple known vulnerabilities.

I would be surprised if these systems haven't already been p0wned a long time ago.