True, if you run it behind a web server like 99.999% of all users.
If you run it as a cli script, you can implement pretty much anything. I saw a ftp server once. Crazy.
Still, even on a normal web server, php can do long polling perfectly fine, which is often enough.
> being able to write program flows without dozens of promises is a breeze
It is a breeze with async/await too.