The problem was never the system. It was that only one person could run it.
You already keep the whole picture in your head: which service owns what, the safe way to deploy, the log line that means trouble, the workaround everyone forgot to write down. It works — right up until you are on holiday, or you move teams, or you simply want a weekend that stays yours.
So the knowledge stays tribal. A teammate hits a wall and pings you. On-call wakes someone at 2am for something you could fix in a minute. New hires spend three weeks learning what one good page could have told them on day one.
The fix is refreshingly ordinary: one runbook per system, a shared structure, and a habit of writing the answer down the first time you find it. That is the whole idea — and it is the whole product.
You do not need to be always available. You need the system to be followable without you.