What puzzles me though is that the article tries to argue that on one hand the cloud concept is no different from client-server as it stands but on the other that the problem is the lack of interoperability.
A random Microsoft server can no more interoperate with a random Oracle or Apple server than a cloud service can so exactly how is it worse?
I also think the term cloud computing is just a bit jumbled. I think of it as the Amazon model, you basically design your server as a VM and then multiple copies of that get instanced as needed. The strange thing is that model is far more vendor neutral than anything currently on the market. In theory there is no reason why any company with the hardware resources can't fire up 1000 copies of that VM if you choose to change vendor. In effect cloud computing by that definition (which I believe is the most common) is no different than leasing servers from a hosting service at present, it just scales a lot easier if you need to.
The economic comparison is equally false. If for example Amazon were to oversell their hardware by 10% then all that happens is the sites they host end up running a bit slowly and people move off the service. The whole company doesn't end up in negative equity and going broke because of that. That metaphor just seems so wrong in this situation that it pretty much makes no sense.
If we were seeing a situation where web hosting and data center companies were merging wholesale while pursuing shaky business models then you could argue that there was a comparison but we are not. Cloud computing is a technical development, and until we see huge companies hosting the entire internet there is no real risk.