Which suggests a test for your understanding of a market: can you map out the incentives and explain why what looks like apparently-irrational behavior is happening?
For example, in healthcare, we waste 30%+ of the $3T we spend each year. Much of that waste is due to hospital readmissions for an ongoing condition like heart failure. Startups sometimes try to fix this by developing a special machine learning algorithm to predict readmissions and apply an intervention. But even when the technology succeeds, the business fails: hospitals charge for readmissions, so there's an active disincentive for the hospital to buy the product. (That is now changing with ACOs, and a change in incentives is an opportunity for new companies.)
While the payers have the incentive to reduce readmissions (saves them money, leading to lower insurance premiums for you), they don't usually have the access to do so -- they're not the one seeing the patient or prescribing medicine.
The payers could, of course, try to change the way that THEY reimburse the hospital to align the incentives. For Medicare and Medicaid, that requires a law--which is why the Affordable Care Act is creating opportunities for new startups as it rolls out. For private insurance, I think they'd like to change reimbursement, but they have relatively little market power compared to healthcare providers:
 Completely different set of incentives (and thus problems) in other healthcare systems.
There's an inevitable conflict between "Make as much money out of patients and the entire health system as possible" and "Care for patients as efficiently and effectively as possible."