Laptop only, not desktop, super slow last night internet, so looking of a culprit and see this:

https://postimg.cc/MXmkH314

Why is CPU not there? So slow, unusually internet everything else barley came up at all. Also any clues from this screenshot culprit? Maybe because laptop is 8 years old itself? Someting in hardware? Thanks

When something occurs that is otherwise inexplicable; my first reaction is to restart the computer. If the problem continues, I will perform a cold boot (power down completely, wait several seconds, then boot). In my experience, that resolves most such occurrences.

I've gone past the restart and now shut down by default.

Shutting down not only cures all ills that a restart cures, it eliminates the potential need for a second procedure, i.e. a shut down after a failed restart.

Is there anything faulty in my logic?

Your logic is perfectly sound, but I suspect most will try the reboot first on the theory that it is faster, easier, and might work.

I felt that way years ago, because shutting down/starting up took more than a minute, but it now takes 30 seconds at most, which isn't a heck of a lot more time than a restart takes.

Yes, an 8-year old laptop could be the culprit. When I look at my "modern" 6-year old iMac with 16 GB of RAM and a Quad-core Intel i5 processor, my System CPU usage is under 4%, where yours is almost 64%.

Something is not right and it goes beyond Activity Monitor. It isn't unusual for the Kernel task to be at or near the top of the list of CPU using tasks, but for the system to use 2/3 of the possible CPU cycles ❓❓❓Neither is there any indication of any user task using the remaining 1/3 as indicated by Activity Monitor. Either there is a total runaway task running, or Activity Monitor is completely knackered.

Personally I wouldn't put any reliance on what keys' Activity Monitor is reporting other than something is haywire. Which is why I suggested a cold boot just to stabilize (hopefully eliminate) whatever is going on.