Re: shout out for storage?
I work at place with a supercomputer. Most of the storage isnt there to keep data per se. In the TLDR terms, the HPC gets data from its sources, does a whole bunch of modelling and crunching then sends the results to the people that want it (I dont want to go into too much detail of who or how for confidentiality reasons).
So you essentially get a whole load of stuff in, it gets crunched essentially in RAM and CPU (its a many/multi node system, not just one fat CPU!) and spits the results out and the original data in essentially gets discarded. Anything that needs to be archived goes to a traditional compute/storage type system which we all know and may not love. The HPC has no need for this once the crunching has been done as a new model needs to be run almost continuously and the old one is no longer relevant.
This is our particular use case anyway, others may have huge storage arrays for their use cases as you mention.