He kind of lost me on his opening CGI argument. Most PaaS I am familiar with don't run PHP through CGI at all. Either Apache mod_php or nginx php-fpm. I guess the author means a CGI-like model or something?
Most of the same things we say about PHP deployment (it's easy, can be done in one file, etc) could equally be applied to writing CGI scripts in Ruby or Python. PHP is just a more extreme example of CGI, and arguably easier, because there's so much support for PHP-based CGI compared to Python/Ruby/Node CGI.