And more importantly, what utility does that have for the network?
The whole idea in their heads is that nodes will "validate" transactions. Which doesn't make any sense because it's the person engaging in a transaction (on either end) that cares about the state of the blockchain, not some random neutral third party. Your full node can detect an invalid transaction all day but without a way to tell the guy who's about to treat that invalid transaction as valid, the utility isn't there.
No, the real threat to the Bitcoin network is and has always been that a hostile actor would get 51% hashpower (or almost 50% but not quite and roll the dice until they won a few blocks in a row) and issue double-spend attacks.
