Even getting to that point requires a lot of training for the IT people, more storage, better data and user-profile management, performance optimization for networks, backup, recovery, archiving and compliance, and the need to buy and manage devices that could be PCs or could be dumb terminals.
It's more flexible than PCs, but is not a money-saving proposition.
Going one step further to virtualize tablets or smartphones means making uncomfortable partnerships with hardware vendors, forcing hypervisors, profile management and security onto a form factor that wants only to be Clever, Beautiful and Free (TM Apple Computer and Steve Jobs, license available only with fully licensed copy of Steve Jobs doll).
Virtualization, and eventually cloud computing, will, as IDC predicts in another end-of-year encyclical, change the world of computing.
A lot of it will be kind of a pain in the butt and only marginally worthwhile for a lot of people, though.