http://www.cccbc.net/mardyl/94 Cloud architectures and cloud business models are not one option. No – they are the default pattern for future enterprise computing. It does not matter if you really use the multi-tenancy capabilities, or if you really embrace an OPEX relation between the corporate IT and the lines-of-business to turn your virtualized data center into a private cloud.
see this page What really matters is, that software vendors build these features into their software platforms to support cloud providers at scale. At the same time – if architected right – the same next generation of software runs leaner on premise – even if you use only one tenant. Modern architectures are simply scale-out architecture and have APIs to manage and bill the usage – which is a typical cloud provider requirement. Using the next gen software, built for the cloud, does not harm on-premise, but provides the urgently needed interoperability in hybrid cloud scenarios. Over the next years larger enterprise will stop treating cloud computing as a separate category and embrace it as mainstream architecture. At the same time the business model of corporate IT departments will try to become more similar to public cloud providers than ever.