[ksec]

I think it is quite clear there are insane amount of money going into HPC like segment. There was a recent tweet about so much Compute Required it nearly took down two AWS Region. I am starting to think Web Hosting in traditional sense aren't really the target customer AWS looking for anymore. DO seems to be fitting the niche better.

[semi-extrinsic]

I think you're right there's large amount of compute power being used on simulations/computations of some sort on AWS. But I don't think they are "HPC", which is understood as requiring rapid exchange of large amounts of information between nodes. It's more like a "non-HPC compute cluster" which are also useful and which you find in many places both in academia and industry.