Why don't ETH transfers cost more when the recipient's balance is zero?

Question

The SSTORE opcode has differential pricing depending on what the original, current, and new storage values are (see EIP-2200 for the full details). In short, the idea is that setting a zero value to a non-zero value (e.g. 0 to 42) costs significantly more than setting a non-zero value to another non-zero value (e.g. 42 to 1337).

However, all standard ETH transfers cost the same, namely, 21,000 gas. Why?

Why don't ETH transfers cost more when the recipient's balance is zero (compared to when it is not zero)?

For example, why not something like ~5k extra?

Sender	Recipient	Recipient's Balance	Gas Cost
Alice	Bob	4.2 ETH	21,000
Alice	Charlie	0 ETH	26,000

Answer 1

I guess this has to do with how accounts are stored on disk, basically once an account is created the entire tuple (nonce, balance, code, storageRoot) always exists, even when balance = 0. note that storageRoot is just the hash of that account's storage trie.

on the other hand, the storage trie is sparse on disk. all values are 0 by default, so by setting a storage slot to 0 you can also remove it from disk.