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