With your help? The moment you declare (or any friend declares) a relationship in the profile, they 'have' you both.
If someone wants to talk to me I get a popup on my Messenger app on my phone, and if I get an event invite it shows up there too.
Good for them, but they seem to mistake it as some sort of universal lifehack.
Does it have to be universal to be useful? Helping 0.01% of the US Facebook userbase save 1 hour every week is still huge...
So, that's one downside, I think.
There's a few communities that I'm in that I wouldn't even know about, event-wise, if I wasn't on Facebook. I can't imagine missing those- I'm surprised others don't use Facebook more for events.
As others have mentioned, I also use News Feed Eradicator, so I don't even see anything on Facebook, unless it's one of my close friends. It's fantastic, and my time on the site is probably less than 2 minutes/day.