Well there obviously is interest in running simulations and other HPC applications on systems of public commercial cloud providers and there are specialized offerings including high performance interconnects, GPGPUs, large memory VMs and schedulers. Don't expect the largest of the top500 clusters to be replaced anytime soon by such, but for lesser demands people will be maintaining spread sheets and calculating the break-even point of renting vs. owning so to speak.

I'd expect in the long run, there will be only few data center operators.