Compliance is the biggest challenge w.r.t. becoming healthier. You need either a really compelling reward at the end, or a severe enough punishment to enforce compliance.
Those are very abstract, I didn't start watching my sugar intake until a close relative got diabetes, despite the fact I had distant relatives with the disease, I saw it every day, and I consciously understood that it was something to avoid. Unfortunately people don't "get" things until they are too close to avoid, a lot of the time.
The problem is that the feedback from the behaviour is not immediate. This is ultimately why it is not easy to be disciplined about a lot of things for which the results are only apparent after a long time. There is no easy way.
I don't know about that (meaning I really don't know, not that I think you're wrong). I know that a lot of time (and money) in nursing and hospital policy is aimed at the huge problem of patient compliance and what can be done to increase it. And I wouldn't doubt for a minute that insurance companies wouldn't love to "influence" policies toward lower-cost interventions using compliance issues as their leverage.