I've been shown how network time is enforced, but I'm still having trouble understanding how a false old block cannot be inserted into the blockchain with the entire chain remined or how a powerful miner cannot remine the entire chain.
Does difficulty prevent this because it would take so long to remine the entire chain, or is there another way that "old blocks" are forbidden?
How are new blocks distinguished from old blocks or new transactions distinguished from old ones?
If blocks older than 2 hours are rejected, how are old blocks never rejected?