@ZachWeinersmith I think it's (at least) two different issues, one of which is 'we don't really know how properties scale down at this level, only observational data and theories that seem to work pretty well' and the other is 'know the internal structure? I want to live in your reality'.

This is mostly just me observing what people who know a lot more than I about this stuff seem to be saying, though, my materials science knowledge is...minimal.