You bring up an interesting and relevant point about how various APIs are used by the applications. But when I think about how the world of software is evolving, it seems that those management APIs are becoming more important, because a software application of today must know not just how to run, but also how to be deployed.
I believe it is both difficult and important to align with dominant designs. 30 years ago it was a good bet to develop software for the new x86 architecture, 15 years ago it was a good idea to bet on the new world-wide web, 10 years ago on the new LAMP stack. Today, the API layer is where different pieces of software come together and where brilliant software developers congregate. It's about AWS, but it's even more about the new design paradigm that the AWS APIs represent. Of course there will not be just one set of APIs. We know that in addition to AWS, we have OpenStack, Microsoft, VMware and Google are all building theirs. One of them will be dominant. Randy Bias brings forward an important point.
The rule on staying alive as a program manager is to give 'em a number or give 'em a date, but never give 'em both at once.