Why not just ban all commercial advertising in public spaces and online? I don't think anyone thinks advertising is a public good, why do we tolerate it?
It's not simply a matter of raw percentage, it's also a matter of advertising value (eyeballs) which is a different question. A significant amount of the most valuable space is publicly regulated, such as along highways. So for example in the US four states ban billboards entirely (Alaska, Hawaii, Maine and Vermont), and it's really nice even just driving through them. For Maine and Vermont (since they share land borders with the rest of the contiguous 48) it actually makes for quite the state border transition in some cases, where leaving you suddenly cross and instantly face a pile of advertising. It doesn't have to be that way though, and as a quality of life goal it wouldn't be wrong for people in other states to give it some thought. Constant ads IRL may somewhat fade into the background just as in other contexts, but that doesn't mean it has no impact.
There was a move in the 1960s led by the wife of President Johnson to get rid of them. One success was, I believe, a freeze on erecting new ones on interstate highways. I don't know how well that worked, but they don't seem to be the worst offenders.
Still it's a good cause.