You can start with a plain HTML page and go "Hey, I want to do X" and just throw some code in the middle of the page. When you decide you need a database, MySQL is right there and easy to use. When you decide you need some libraries, you can just download and `include()` them. All of this can just be FTP'd up to some server somewhere.
As this grows bigger, there are tools like composer and frameworks/libraries like Laravel and Symfony. You can still FTP those, but once that gets painful you can start to learn the bit of *nix skills it takes to start managing this different ways.
At no point have you had to worry about nginx/apache/supervisor/anything else. But whenever you're ready, that's all there too.
This is basically the path at least one guy I know took to going from working in a totally non-technical industry to building a massive (almost 2 million lines at this point) application that allowed people in the industry to stop working with a bunch of exploitative big name companies and instead self-manage and earn more money. And now that product makes a bunch of money for him.
And then there's the scales that places like Twitter/Facebook/etc took it.
I think the big thing that always gets missed here is PHP's... egalitarian nature. Yes, at some point it just ends up a in some ways less-good version of other things. But it provides an incredible opportunity for people who aren't engineers to realize their ideas without immediately becoming overwhelmed with needing to learn a huge amount of foundational knowledge before they can lay down their first line of useful code, and seeing that through to crazy places.
And if you are doing something moderately complex/serious/modern you probably need/want composer anyway - because uploading all of the million files via FTP is cumberstone (let's not even get into the versioning/modern deployment practices). Then you are at shell already and not that far away from other language deployments.