Minor historical pontification on my side: The term 'cloud' is only the current term for an old idea. Before cloud there was 'grid'. Before that was the Amoeba OS and other distributed OSes. Long before that, a 1960s hope for Multics was that it would be:

> ... a utility like a power company or water company. This view is independent of the existence or non-existence of remote consoles. The implications of such a view are several. A utility must be dependable, more dependable than existing hardware of commercial general-purpose computers. A utility, by its nature, must provide service on demand, without advance notice in most cases. A utility must provide small amounts of service to small users, large amounts to large users, within very wide limits. ... http://www.multicians.org/fjcc3.html

That's shortly after the CDC 6600, and before the DOE really got into the supercomputing business.

In any case, I don't know the politics of supercomputing, and my experience in that field is even older than yours. When I look at current clouds systems, and try them out, I throw my hands up, because they don't handle the types of architectures I use in my research. I do compute-heavy work on medium-sized data, with algorithms that works best with stateful nodes in a boss/worker system. Luckily for me, I don't need low latency, so building something on top of ZeroMQ is good enough for what I want, and easy to do.