[notaspecialist]

You don't need to have cookies on your website unless you need to reconnect the browser to a session where you're keeping their authorization etc. Unfortunately most people just want to run a website to do something and the easiest thing is to use WordPress or whatever the popular framework is, which has this cookie behavior built in because it "might" be needed.

I browse with all cookies blocked, except on sites which I need to login with. This sometimes gives me a "enable cookies to use this website" message but I just move onto the next website in my search.

To answer your question however, website owners need some analytics to know if their site is getting attention, what people click on, where they go. It really helps to improve the UX and reinforce the 3-click rule (your visitor should get to the page they want in 3 clicks). Perhaps if an analytics package was part of every framework, less efforts would be placed into using external companies which must monetize people. Just a thought.