You do not need a banner, you need informed consent. I'm sure there are other ways of getting consent other than a half screen pop-up with a big red accept button on first visit, but they probably won't get 70% "opt in" rate.
Law: You have to get some form of affirmative consent if you want to do specific often-abused things.
Companies: We'll do it in the most obnoxious way possible ("here are our 853 technology partners... no, there's not a 'deselect all' option, have fun clicking") so people blame the law instead of the industry that didn't want to allow consent at all.
There's always a deselect all option (or rather, the equivalent "accept only the technically required ones"), because it's required by law. Sometimes the operator tries to hide the option. That, too, is illegal.
Companies: Annoying banners.
Legislators: Mission Accomplished. A win for the good guys!
Situation persists for at least a decade.