[vbo]

I've seen server-side rendered websites that took several seconds to return a page, while not being under any particular load. How is that different?

Of course a static html file will load instantly and likely not cause any issues, but apples to apples would mean comparing dynamic server side rendered websites to dynamic client (or hybrid) websites. In both cases, inexperienced developers can make a mess of it, including by picking the wrong kind of tools to do the job.

I think JS gets part of its bad reputation because of the ads (and ad networks) it empowered and the bad practices they turned into status quo (reflows, cpu usage, to say nothing of in-your-face overlays and that kind of stuff).

[bdcravens]

Slow loading server rendered would also be a slow loading API. At least with a slow server rendered app I as a user (not a developer) knows something is happening. A fully formed client with a slow backend can give the wrong impression that the app is working (unless the developer reimplements "loading" feedback that the browser implements natively)