It would be nice, but it's easy to see why they don't.

Assuming the customer set that wants a supported orchestration tool, it would allow those AWS customers to more easily leave for Azure or GCE. Perhaps more importantly, it would allow existing customers to have credible on-prem dev, test, or disaster environments.

When you have the sort of market share AWS has, there's no real incentive to open those doors. I suspect this won't change until/if this market is more balanced.