Wasn't the internet literally created by the military for military comms? The decentralized routing was in part to ensure that comms could survive some areas being taken out by nuclear weapons.
The decentralized internet is less of a reality today than it was years ago.
The web though I agree isn't very decentralized.
An attacker (read: nation-state actor) wouldn't even need to take down US-East-1, it could just take advantage of the outage.
I assume (hope?) there's some kind of backup comms plan or infra in place for critical events, but I don't actually know.