On-chain ads can work, they already kind of exist in the form of promoted posts, it's just a matter of displaying those posts correctly. But it's not too hard to imagine a world where front ends display ads, then get paid in fiat, buy hive with it and give it to the authors who got the most pageviews.

First this creates obvious buy pressure and authors are incentivized to share their post outside of hive instead of inside of hive to whales. resulting in more outreach => more content creators / investors => higher coin price => more investors etc