[tabtab]

> And what happens when I rotate my device? Or resize my window? ... or switch to night mode.

It tells the server and the server re-renders the page. It's a bit slower than client-side adjustments, but worth it for the extra power and control. I don't do those actions very often, do you? The existing tools screw those up anyhow.

> But I really don’t think making them less flexible is the solution. If anything they’re not flexible enough

That makes the client even more bloated, meaning more client version variation and bugs. That exacerbates the problem. By shifting the burden to the server, the client can be simpler and thus less buggy, and the server can pick the best layout engine for the domain instead of being stuck with the client's one-size-fits-all mistake.