An enterprise can have RedHat in a minimal install using Kickstart. Then separate functionality can be layered over that for a desktop, document server, RDBMS server, DNs server, ... . Then there are only a few platforms that scale across the organization.
This is very different from the 'personal computer' paradyme and much closer to the 'terminal of a mainframe' model. But until the enterprise limits the number of platforms that need to be tested and debugged, no maintenance effort will be able to scale.