[hueving]

>2. There's a common API for requesting new instances and performing maintenance tasks

Only true if you commit to vendor lock-in. If you use a higher-level cloud agnostic library, then it likely works with openstack as well so you can manage on-prem and off-prem instances the same.

[TheHydroImpulse]

At a high enough scale, you have a lock-in _somewhere_. Spending time trying to abstract yourself from any lock-in can be wasteful.