I do recall it being common for internet ads to be sold directly like billboards back in the day, before the action model took over, especially for higher value sites that could be likened to the prime real estate of a billboard on a city square or key highway with their guaranteed literal traffic.
But such direct deals probably didn't scale well, and definitely left smaller sites wanting to earn some extra revenue in the dust. There was a time when ads weren't as shit as they are now - most wouldn't worry about a banner ad or two on their favorite forum.