This isn't the only thread to talk about this stuff; there's been jillions, though none I've found that talks about exactly what I'm discussing, mostly just people talking about what the different "forms" of memory are.
I notice that this thread (Inactive memory) from 2004 correlates with the Apple description
So I'm wondering why, among other things, my Inactive RAM isn't being converted into Active RAM? Instead the system pages out and uses swap space?Inactive RAM may be thought of as a first stage swapfile. It contains instructions and data that are not currently in use within the OS or an application, but is left in RAM in the event it is needed again. If more Active RAM is needed, the Inactive RAM will be reassigned and if it contains data for a currently open application, that data will be rolled out to a swapfile. Otherwise the memory will simply be overwritten.