Yes, yes, yes these are all good ideas, but they are all based on the preset technology, the present paradigm.
Maybe it would help if I framed this as a kind-of pretend game? The only rules (parameters, really) as to what "your" picture/perception (invention?) should be like is the ability to connect it to some means of present technology as a link or a stepping stone. Let me give you an idea on another technology. I'll call it the "Plasma Drive."
First some baselines,
-=o=- Present memory is held in place due to electromagnetic forces held within a physical framework, eg., the "chip."
-=o=- Since the "chip" is a physically delineated entity, it is finite.
-=o=- Plasma is energy in flux and in disorder, but it is not limited by finite "physical" boundaries.
-=o=- Theoretically, the energy within the Plasma could be ordered via other external and stronger electromagnetic forces.
-=o=- If the above were true, then the particles in the Palsma or at least a region could be "defined."
-=o=- If Plasma regions could be "defined" then it could be possible to set these "regions" as bits, 1 or 0.
-=o=- If this could be done then a memory core could be "defined" as a 3-D "grid."
Now, with all tis as a foundation...
-=o=- With only technology limiting the defined "bits" and therefore quantity of memory, then the storage capability could approach infinite as technology allowed for ever greater precision of the "regions" in precise subdivisions.
-=o=- Voila` - the Plasma Drive that eventually can handle an EB of EBs in a "case" the size of a sugar cube! Who knows, since the reions are no longer tied to a simple on-off state, perhaps each "bit" could become a "superbit" capable of having multiple states? How powerful would that be!
Ok, granted, this is far-fetched to our perception today, but back then even Bill himself couldn't conceive of anything larger than 640K, right?
As we go forward with this "game," try to let go of all the present perceptions and see what your fertile minds can spawn. I realize that this doesn't seem to have a connection with the present need (fall-back), but who knows if some far out idea might provoke a new way of using the present resources?
I hope this helps.