Yup, the interesting data point would be what did Amazon pay for their oracle usage vs smaller companies? I would guess that as long as Oracle gave them a reasonable price Amazon would be happy to stay on - except for a question of long term independence and vertical integration.

Amazon is probably in a unique position in that providing data and database services is a core competency, and so vertical integration off of Oracle makes a lot of sense even separate from the cost leverage question.

Yes and AWS also built multiple database types to meet their needs. Is your company going to do the same?

What? No, but that's my point. Even a company like Amazon was locked-in to a vendor. I'm not saying people should build their own databases but that this is a move in the right direction.