The fatal flaw of this article is assuming that having a single PHP file implies ugly code, or at least uglier than the average codebase.

I would, in fact, guess that its code is much cleaner than the average Fullstack Javascript app.

If you're capable of writing a full, functional website in one PHP file, you know what every line of code does, you have only what you need and the ways to factor your code become more obvious.

Using the "modern" Javascript stack usually means that you had to spend months or years trying to learn this mishmash of Javascript libraries (React, react-redux, Express, an auth library, an ORM, etc.) and you don't know what most of those things do under the hood.

The lesson I take away is: Simple (PHP + Jquery) can be better than complex (React, Redux, Express, Passport, etc).