In my experience, the option is usually hidden (look for “options”). But a surprising number of sites do actually comply and make this not prohibitively obscure.
Meanwhile everyone else doesn't understand these pop ups, doesn't know anything more post GDPR, and they just roll through them and get tracked just the same.
In effect we have big annoying pop ups and little seems to have changed. If we care about the ideas behind GDPR, I think we have to recognize that it may be failing miserably in practice.