I've written quite a bit of PHP and jQuery but with that approach there's a decision when you consider writing the code if you're going to implement the feature in PHP or in jQuery. The difference with the upcoming generation of JS frameworks is that the server and client are in the same language so the decision can be deferred or it can be determined automatically.
Astro, for example, is very conceptually close to PHP. Your code runs on the server, there's a code section where you grab content from the DB and a markup section where you template out the page, the lifetime of everything is one request, etc. What's changed is that you can put an attr on a component indicating you want that component sent to the client. No attr, it's old PHP, attr it's jQuery, and further the send can be triggered can be when the element enters the viewport or when it's clicked.
In the in-development Marko 6 runtime distinguishes between url/db derived "settled" data and client side/event handler state and only sends the latter to the client. If you have a paged list (for example) you can set up the prev/next page buttons to be links and you wouldn't have any JS sent down to the client despite the app being written with current SPA component ergonomics. If you'd rather have the data fetch and render client side you switch the data declaration from a const (dervied/settled) to a let (state) and all the rendering JS gets sent down.
I'm simplifying/omitting stuff but these are new and useful takes on old ideas. I think better takes on old ideas are some of the more effective advances in the state of the art.