I’m not sure why you’re being downvoted. I feel the same way. I’ve been invited to multiple social events that were largely organized on Facebook since deleting my own account. I was always informed either directly or indirectly through mutual friends, usually by phone or SMS/iMessage. I’ve also been made aware of multiple events I did not attend because I do not consider myself close friends with those hosts and I’m happy to avoid that awkward ‘has not responded’ status that Facebook would mark me with.

In a world with email, SMS, and iMessage I do not fear being left out by my true friends.