Hell, in PHP 5 era and before, it even HAD to, PHP had been designed as "you get a brand new process every request" and so a lot of things with memory went wrong if you ran for too long.
This changed with PHP 7, some framework appeared to allow an event based system, and then PHP 8 (or a later minor update) added fibers to the core to support it more easily.
These day, event based php has several well supported frameworks, is stable and fast, and allows you to have the same codebase on your websocket or other event system as you use on the rest of your app (sharing libraries is super cool, using the same DTO on the sender and receiver also, etc ...)
Does it also run in the browser, so you can share type definitions and libraries and tools between client and server, and seamlessly perform isomorphic server side rendering?
If only there were a language that was as universally deployed and well supported and extremely optimized on both server AND client, and had all of the capabilities of PHP and many more...
Because today, using an anisomorphic language that can't run on both sides is like riding a bicycle with only one leg.
Oh I would agree but Javascript is anything BUT stable in its environnement and frameworks etc... Trying to update a one year old php code base with composer means no issue at the end in 99% of the time.
Oh don't worry, some day JavaScript will as stagnant as PHP, too. Just wait, time flies.
If it's a stable environment that runs old code you want, then if I had my way we'd all be programming interactive distributed network extensible web apps in PostScript instead of JavaScript, and that language has been stagnant for a much longer time than PHP has ever existed (13 years before PHP 1.0 was released in 1995), since you can still print and view all of your old PostScript documents from 1982, 42 years ago.
HyperMedia browser with embedded "applets" in PostScript:
It's definitely the only worthwhile or practical language for isomorphic web app development.
Of course you could choose to run a WASM PHP interpreter in the browser, but you be you.
Or you could petition all the browser vendors to support PHP directly. Get back to me on that when you've sorted it all out and resolved all the political and technological and economic issues, and also implemented a better framework than SvelteKit with it.
I thought php has a per request execution model.