"We" referred to US healthcare spending [1], and the party with the right incentive for this problem is the payers: Medicare, Medicaid, and private insurance like Aetna, Blue Shield, United Healthcare, etc.

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: http://rockhealth.com/wp-content/uploads/2012/12/Kocher-et-a...

[1] Completely different set of incentives (and thus problems) in other healthcare systems.