People who are passionate about the subject they are writing on are going to publish regardless of ad revenue, assuming they get hits (writing stuff nobody reads is a fast track to burnout). Right now, in many cases these people are being crowded out by well SEO'd content mills. If the advertising dollars dry up, the content mills will die off, and that ecological niche will be freed up to be filled by people with passion.
I for one welcome the idea of a return to a genuine internet, where everything isn't about monetization. The amount of content may go down, but the quality will almost certainly go way up, and there will be that much less garbage to wade through.