True, I too have never seen a WebSocket connection stay up for 7 days--1 day is rare, but in my thinking, WebSocket "events" are not like a Request/Response cycle of HTTP. Each message is one-way and you would never be waiting on an external fetch. A WebSocket upgrade cycle could take longer and involve an external fetch but I don't think of that as an event. That's the only part of WebSockets that involes a traditional HTTP Request/Response.
Some clarity on this would be nice, but I have to say that I have never knowingly had a WebSocket "event" hang on me so I'm not even sure why this setting is in there. Someone must have experienced hangups at some point, is my best guess.