And it would solve nothing.
GDPR already mandates that "Refuse non essential" button should be the same size and prominence than the "Accept all" button, every website around the globe does not care (apart from major players like Google, Apple or Amazon) and national data protection authorities absolutely do not care.
We already had one attempt with "Do not track" header, nobody was willing to commit to it because it impaired business. Same would go with OP proposal.
Websites are forcing this banner on us because they are greedy morons that would rather drain our data for money than incite us to pay for their work.