Comment on your first point— I have done the work you speak of (porting AWS-specific code to other cloud providers). It is absolutely possible and relatively pa

Comment on your first point— I have done the work you speak of (porting AWS-specific code to other cloud providers). It is absolutely possible and relatively painless if you design for that feature at the outset. Almost all of the lower level AWS services have a counterpart in the other ecosystems. So if you build the right interface abstractions around those components, it gets you a long way.