The idea feels like sci-fi because you’re so used to it, imagining ads gone feels like asking to outlaw gravity. But humanity had been free of current forms of advertising for 99.9% of its existence. Word-of-mouth and community networks worked just fine. First-party websites and online communities would now improve on that.
The traditional argument pro-advertising—that it provides consumers with necessary information—hasn’t been valid for decades.
Also roadside advertisements for services are also acceptable, what I mean is something like Peggy Sues dinner where they’ve got some signs to let you know which off ramp to take. Frankly speaking allowing gas stations and food places to advertise off the side of the highway is pretty reasonable to me, even in the modern era with phones the usefulness of them can very either because you don’t want to look at it while driving or it’s just got no signal.