I think the problem is that we have one network doing many things that need to have builtin redundancy both in terms of messaging and data storage. So putting a bank's entire database into Azure or AWS isn't wise in my opinion. Rather, I think the network either needs to be fragmented to serve different sets of customers or the end points need to be improved to the point that onsite hosting becomes the norm again. Centralization is much like specialization in that it can be adopted to the point of diseconomy.