It's funny that this is even necessary though - that great EU innovation at work.
The transparency requirements and consent for collecting all kinds of PII (this is the regulation) actually is a great innovation.
If a user logs in or does something requiring cookies that would otherwise prevent normal functionality, prompt them with a Permissions box if they haven't already accepted it in the usual (optional) UI.
But yes, I think just about everybody would like the UX you described. But the entities that track you don't want to make it that easy. You probably know of the do-not-track header too.
Google could've implemented a consent API in Chrome, but they didn't. Guess why.
The industry knows ~nobody wants to be tracked, so they don't want to let tracking preferences to be easy to express. They want cookie notices to be annoying to make people associate privacy with a bureaucratic nonsense, and stop demanding to have privacy.
There was P3P spec in 2002: https://www.w3.org/TR/P3P/
It even got decent implementation in Internet Explorer, but Google has been deliberately sending a junk P3P header to bypass it.
It has been tried again with a very simple DNT spec. Support for it (that barely existed anyway) collapsed after Microsoft decided to make Do-Not-Track on by default in Edge.