How would you know. did you ring the doorbell and as "hey, are you guys well off?" What does it mean to be well off anyway? Sometimes people who save a lot of money appear poorer than they are.
I know my neighbors exist -- I share a wall with them. There's thirty families on my block and I don't know the names of a single one. I think I've said "hi" to one once, when we happened to be on our balconies at the same time. But what ocassion would I have to talk to them?