Honestly? I think if people think it's tough to get traffic out of Google with organic rankings now all they have to do is wait a while and they'll get a taste of how tough things are going get.
IMO the canibalization now is nothing compared to what we're going to see moving forward, but that still doesn't mean they need to "manipulate the order the organic results are displayed in based on how much an entity spends on AdWords", because all they really have to do is keep trimming down the number of organics on the page as they pick up more relevant advertisers to display above the organics.
It's really simple for them to make more money and get more ad clicks and clicks on their properties based on design, prominence, and number of organics on the page. They don't need to manipulate the order the organics are shown in (1 thru N) in any way, all they have to do is change the design and show more ads and more of their properties with more prominence to take a bigger % of clicks away from the organic results.