Indeed, but that's exactly the point: influencing opinion higher up the status hierarchy is more difficult and more effective.

Far, far harder overall. But if you have money (or other power substitute) then the high status people are easier to buy. Not only are they already (on average more) corrupt they are also a lot better at adjusting their beliefs according to what will benefit them. That is, after all, a big contributor to getting the high status in the first place.