I can't speak to any kind of general principle here, but viewing any standard modern web page e.g. Twitter, Discord in a Web browser reliably takes more CPU and memory than running a late-game Factorio save.
I will allow that it is probably theoretically possible to do client-side rendering in a CPU-efficient way, but it sure isn't the standard.
I will allow that it is probably theoretically possible to do client-side rendering in a CPU-efficient way, but it sure isn't the standard.