In the "bitcoin=internet" analogy, the core broadcast network (the blockchain) is equivalent to the Internet layer (IPv4)--the layer that routes most internet traffic.
Flawed analogy is flawed. The network is not the blockchain, and neither of them are a protocol, which makes neither of them analogous to IPv4. And that's just problems #1 & #2.
Now you're just being pedantic. The blockchain is the ledger that commits to the activity of the broadcast network. Doesn't change anything. Bitcoin is a protocol, specified by the behavior of the reference client, which encompasses all of this.
Feel free to explain how the bitcoin protocol is not analogous to IPv4, rather than just stating that. My comment spoke to the nature of broadcast networks, and the use of additional layers on top of IPv4 due to its shortcomings.