That's why mechanism design [1] exists as a field of study. The whole idea of that field is to provide the proper incentives to steer the participants towards your objective. Yes, considering they will try to "game" the system however they can.
I'm pretty sure google could do strictly better (i.e.: better in all reasonable accounts) than they do now if they focused on the users' experience instead of revenue for a couple terms.
Paul Graham says Google doesn't want to follow anybody down that road (human intervention in search). But ISTM the problem is that even though they don't, they can just throw a giant pile of money at it if they needed to crush a competitor. Also, VC will refuse to invest in anybody doing it because Google.
I'm pretty sure google could do strictly better (i.e.: better in all reasonable accounts) than they do now if they focused on the users' experience instead of revenue for a couple terms.
[1] https://en.wikipedia.org/wiki/Mechanism_design