That's not the argument though - the argument is that storing high security rarely accessed information ( hashes of passwords / encrypted passwords ) that are n

That's not the argument though - the argument is that storing high security rarely accessed information ( hashes of passwords / encrypted passwords ) that are needed for a very limited number of well defined operations on the same system within the same security domain with the low security often accessed information with a high number of not well defined operations is what responsible for majority of hashed/encrypted credential leaks anyway. You are going to have a much harder time getting data from a service that only speaks HTTPs with 6 endpoints that can only be fed 1 type of JSON with only specific fields present per end point rate limited to rates per second that make sense for those individual end points with a database backing it being internal to that service which gets 15 deploys per year than from a Gigantic Database Supporting Application That Does Everything For Users and Business and Marketing and Analytics that keeps changing based on weekly sprints.