Yeah, for on-prem scientific work, heavy CPU usage, probably bursty, no need for all the fancy things, security etc. - this is a pretty straight forward case for on-prem use.

Or not even on-prem, just renting some physical boxes from some place where they're only going to have a basic markup.

You have to wait a week to get few more boxes but that's not a big deal.

This is the kind of thing I'd imagine a corp would start doing pretty early, because the 'flexibility' of IaaS just isn't worth the cost.