[ktpsns]

(Mostly academic) high performance computing (HPC) has clearly different needs from what typical cloud computing services can provide. The setup and operation costs of a medium size (~1k nodes, ~25k cores) university computing centre in Europe costs at the order of 1MEur per year, not even speaking about the large national centers with with 10-100k nodes and 100k to 1M cores. At these level of computing it is quite sensible to do it in-house, especially if the engineering challenges are welcome scientific research topics on their own (such as energy efficient HPC, research on distributed file systems or job queueing systems, usage of accelerator cards).

By the way, at one point, in science, there is already such a kind of computing cloud: We call it https://en.wikipedia.org/wiki/Grid_computing