I certainly agree with you when it comes to small and midsize companies.
However, where I really see a potential advantage to cloud computing is very large companies that operate multiple data centers for their own business use. If these companies were able to start using cloud computing for their internal needs, I could see a huge potential for hardware, software, and energy savings. I have seen large companies run tons of servers, all far under their capacity out of a reluctance to run multiple applications on a single box. Virtualization helps with this a lot, yes, but operating with all of the company's computing load balanced across an entire data center would certainly improve the overall utilization of resources.
I think the larger companies would certainly have more trouble getting their infrastructure to a point where this idea would be feasible though.