I don't think it is necessary to require users to run their own nodes, but simply allow the option and encourage a community to form around doing so.
Basically, set up a scenario where the startup is service-oriented and must stay honest because it competes with its own community for users on the official node. Most users will prefer to trust the startup with their data for ease of use, and there will be an enormous amount of credibility gained by having a mechanism to keep the startup's greed in check.
I didn't mention this, but the value and the revenue will come from solving people's problems. I think things are really well aligned here. You have a really cynical view that most people don't share. You're probably closer to reality, but what users actually care about matters more than reality.
I should probably mention that I have put quite a bit of work into developing a similar system myself. I even prototyped and pitched it a couple years ago, but basically got shut down by judges who were offended by the kinds of data I suggested tracking (i.e., everything).
I am quite cynical about companies that extract revenue from personal data (LinkedIn, Facebook, Google, etc.), and I recognize that most people probably aren't. I suppose I am more of an idealist and would have trouble sleeping if I inadvertently created Big Brother, which is why I would risk hamstringing such a startup to try to ensure that it stays honest.
Basically, set up a scenario where the startup is service-oriented and must stay honest because it competes with its own community for users on the official node. Most users will prefer to trust the startup with their data for ease of use, and there will be an enormous amount of credibility gained by having a mechanism to keep the startup's greed in check.