Safari already has this type of thing for a lot of other related features that require (or make sense to provide) user consent - but not cookies.
Maybe it's a harder issue to solve with a UI (third party cookies, subdomain cookies etc.) Maybe they just haven't gotten around to it (I used to set the global "site im visiting" cookie pref but since they added the "intelligent" cross site tracking protection that option seems to be gone..
Maybe it's a harder issue to solve with a UI (third party cookies, subdomain cookies etc.) Maybe they just haven't gotten around to it (I used to set the global "site im visiting" cookie pref but since they added the "intelligent" cross site tracking protection that option seems to be gone..