I'd say it depends on the Linux distribution. Things like Ubuntu would be much like mentioned [1], packing just about everything¹, while on something like openwrt you would probably recognize or easily find out the function of all userspace processes - I counted 13 on my router.
It doesn't help that linux (kernel and userspaces) tends to resemble chaotic patchwork more¹ than a reasonably designed system.
¹ exaggeration
Of course you are correct; “Linux” is a big landscape, and descriptions of instances run the gamut (eg: OpenWRT vs Ubuntu). When I was writing above I had (eg) Red Hat or Ubuntu in mind.
[0] https://youtu.be/URVS4H7vrdU
[1] https://youtu.be/B19a2i3HnJM