Right now, larger ISPs aren't getting large
blocks, and they are allocating things in non-contiguous non-growable
blocks, neither of which is good. Nothing is being done to organize
topological assignments at all, which is seriously not good.
If some registry were to give me a /8, I would carve that up
right now into ten chunks (one per SprintLink POP as of a
couple weeks from now) and subdivide those to take into
account possible growth into new cities before the current
allocations to end users were exhausted, and allow for
unexpectedly heavy or unexpectedly light allocations to
customers from those prefixes.
However, those ten chunks would be the only individual
prefixes announced out of AS1239 to the rest of the world,
in the entire /8.
Some parts of the world would even see the /8 and not the
ten individual per-POP prefixes.
This is what is done now with smaller chunks of address
space:
Block Name IP Addresses