If that’s where this all shakes out to it will have the affect of creating retail monopolies worse than even in the pre internet days as marketing will be simply too expensive for many online small businesses. 90% of Shopify stores would be dead in the water.
Nobody is stopping anybody from advertising or marketing. Simply that if your advertisers wish to track me, then they must ask my specific opt-in permission to do so. And so they should.
If your business cannot survive without illegally (!) tracking and trading in personal data, then you have a scummy business model and a business that has no right to exist.