There are valid questions about how things like rescaling and restoration work, but I think there are good patterns for dealing with this that get into the design of the storage layout and primitives. TLDR, it should be possible to page in/flush chunks rather than everything, but that's obvious.
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So it's exactly what you said. If you design for 'disk as an optimization', you get very different outputs which are way superior. It's a massive investment though.