Someone who prints something for a third party isn’t selling ad space.

Everyone could self promote, they just couldn’t contract someone to do it for them. Employees could promote for their employer, but it couldn’t be subcontracted out. And you can’t pay a company to put up your ad on their billboard or their website, etc.

Ignoring how this might be enforced, would it be enough to let people express themselves while cutting out the impact of negative externalities of advertising?

> would it be enough to let people express themselves while cutting out the impact of negative externalities of advertising?

I think it's doable. But I haven't seen the scalpel yet.

In the meantime, we have clean lines we can run up towards. Banning ads (basically, commercial speech) in public space. Banning commercial bulk mail. And banning targeted commercial advertising (beyond the content it sits).