Dell is a better example
The AWS reference has some relevance but I think a better example is Dell. Dell resold storage equipment from EMC and others and networking equipment from various vendors including Cisco but they decided to acquire the ability to make their own label equipment to go into those spaces and in effect started to compete with their vendors (or so called partners). Now EMC and Cisco compete pretty much against Dell and this is likely to only become a more common situation.
Service providers don't really care about much other than cost. They sell features and capabilities but they are extremely cost focused and in the cloud world where the services provided are abstracted behind APIs the underlying hardware becomes less and less relevant including the expensive software enhancements that vendors provide that also helps the vendor's margins. It is a bit analogous more with the Auto companies in that they really don't care what brand fuel you use and as a result the only real differentiator is their cost and convenience.
Storage companies that don't look to own the data interface layers are ceding control of their future to their competitors and partners which is a good way to find yourself out of business.