Chances are every site he visits, including this one, would be part of the 99% that is gone. Unless his fantasy web is some sort of early 90s Geocities flashback, it requires advertising to exist.
No, advertising today is just the easiest way to monetize a web site. Seriously: sign up for google, and you can make money from grandma visiting the latest grandbaby picture album. Even if it's only a few cents, why the hell not? The vast majority of web content provides no relevant income to its creators, not enough to pay for hosting, definitely not enough to pay for dinner.
If you make advertising pay less, or just make it harder than creating a google account, then people who are actually serious about making a living off internet content will switch compensation models. Their content is likely to become more valuable, because there won't be a hundred other morons out there doing exactly the same thing.
On a normal day, I visit probably two dozen different websites - a mixture of electronic versions of traditional journalism, "web 2.0" blog aggregators, storefronts, and specialty sites. Devaluing network advertising isn't going to hurt the storefronts or professional journalists (who, even today, collect some subscription fees). It might encourage the reddit/wordpress world to impose subscriptions, which would certainly reduce discourse. Most of the specialty sites I visit are people's hobbies - they spend $10, $20, or $200/month on these things from personal passion and because their real life work gives them the means to do so. They're not going to change if the ad networks dry up.