That comparison is complicated: it's definitely easy to drop a .php file on a server but once you start talking about frameworks, using a newer version than your OS distribution shipped, adding C extensions, etc. it's easy to find counter-examples, and the Go proponents are not wrong to observe that deploying a single file is easier than either.
This is also becoming less of a distinguishing factor in the container era where the answer for a number of cases is “Extend a base Docker image”.
At least PHP offers that option at all, and it's well-supported and well-documented. It's also very easy. Good luck doing the same with any other language.
If you really, really try it's possible in Python, C# and Java too, but ... wtf.
Note that I didn't say it wasn't a selling point for PHP. It's just that I can count on no fingers large PHP projects I've seen where deployment is still that simple – and that's generally not a problem because with modern tooling (e.g. Ansible) and deployment options (e.g. containers) you're under less pressure to make that a deciding factor for your application.
This is also becoming less of a distinguishing factor in the container era where the answer for a number of cases is “Extend a base Docker image”.