Okay, if the title is correct, then to heck with traditional RAM and, instead, have very long addresses, say, a(i).b(j).c(k) ... stored in, say, a key-va

Okay, if the title is correct, then to heck with traditional RAM and, instead, have very long addresses, say, a(i).b(j).c(k) ... stored in, say, a key-value store. Then, as usual for caching, just hash that long address. Why do that? Mostly no one really wants the sequential addresses, and a lot of work in software and the processor is calculating those sequential addresses nearly no one really wants anyway. So, e.g., software collection classes, just let the keys be the long addresses and f'get about AVL trees, red-black trees, etc. And for sparse matrices, just use the row and column indices as the addresses and f'get about all the tricky addressing for sparse matrices. Etc.