I appreciate and understand the sentiment, but I don't think anything like this can be reasonably coordinated and achieved. For instance, I wouldn't want to participate in an experiment where I have to spend my SBD or Steem for a type of service I do not approve of.
Additionally, we also need a control, so we need to get people to stop using the vote buying for a period of time to see what the effect will be. But that will never happen as there will always be people who would use the time to buy cheaper upvotes.
But even in a perfect world where everybody in the platform would participate in an experiment, you most probably still wouldn't be able to show clear causal link as there are too many other variables. The price of Steem and SBD depend on a lot of additional factors, not just on the way people are behaving on the platform. Any change you see in the price of the token might actually be a direct result of implementing a platform wide experiment or the people's expectations of the outcome, not the actual thing being tested and you don't have any way to prove if it's one and not the other.
I'm not a fan of vote buying and I have no doubt that it one of the big contributors to people giving up on the platform. Seeing low quality content rewarded with very high earnings is indeed disheartening.
RE: Steem is a Free Market, Therefore Buying Votes is Voluntary and Not a Problem (or is it?)