Delivering both block and object storage platforms out to our users involved our very talented designers, engineers, infrastructure, operations, product, support and marketing teams, so there's no one particular "field" that you need to be best at. ;)
I can speak specific to storage engineering a little bit. I don't think there's a strong requirement of a university degree as such, but having the knowledge (and/or experience) of dealing with persistence (along with the problems that come with it) and various access patterns for large amounts of data would certainly be useful. We have built several services internally that manage information flow and persist metadata of storage clusters, that don't deal directly with the underlying user data but are critical to the control plane and having generic software engineering skills is quite useful here.