For what it’s worth, sama said at a Harvard event recently that he “despised” ads and would use them at a last resort. It came across as genuine and I have the intuition/hope that they might find an alternative.
The original Google whitepaper warned against the exact moves Google made years later with ads. It's fun to go back and read their thoughts on ads and how they completely change the incentives of the search provider. "fun" in that they were right and search quality has decreased considerably because of it.
