Of the things you listed only JS would count as "CPU intense" in the strict definition of CPU as microprocessor unit; the others are typically bound on specialized hardware -- hardware video encoders/decoders, and GPUs.

And, having done plenty of video dev work recently, beyond the codecs and GPUs, it's also memory bandwidth/lock contention/data path that's really key for getting good video performance. We're almost never decoding or encoding video by CPU anymore. If we can avoid it.

Arguably with JS heavy web browsing you're also looking at memory bandwidth or lock contention as a key limitation -- garbage collection in the JS interpreter, fetching and dispatching opcodes, etc. CPU is only part of the story.

Life just became so so very complicated in the 90s when CPU performance started to compltely outstrip main memory and bus performance.

1) I don't tend to think of games as applications with GUIs, but you're right, they really are, and yes, they can be CPU-bound sometimes. However, a game that was actually CPU-bound would be very unpleasant to play. That's not true for the applications that run on super-computers: they just take longer to run that someone would like.

2) video conferencing is not CPU-bound unless you're doing 1-to-many/many-to-1 feeds locally.

3) JS heavy web browsing ... 'nuff said.

4) Very few people do video editing that is CPU bound. Certainly for video editors, it is an issue.

Clearly, I should have said:

  "The majority of applications used by the majority of users are rarely CPU-bound"

But more importantly: even the exceptions are really nothing like "supercomputer workloads".