Where I grew up nobody would ever think about stealing postal mail. It would rate as approximately the lowest concern as a home owner. I never saw a single locked box, they were always simple fold down boxes by the road-side in front of the house. First it's a federal crime and fairly serious to steal postal mail, second most of the stuff in the postal mail would be bills or junk-mail, and third home owners get used to when the postal mail would arrive based on when the postal worker runs their route, so a mail thief would have to have good timing and risk getting caught by the home owner. Neighbors often watch out for each other as well, someone suspicious snooping around your neighbor's mailbox might warrant a call or stop by to point it out.

Most Americans, at least in the past, would be throwing out bank statements in their trash every month (now a lot of it would be digital of course). If you wanted to steal bank details, I suspect that would be the way to do it rather than trying to time the mail and risk getting caught that way.

Name and date of birth are mostly trivial to come by. You can look up modest details about almost anyone in the US for $20 or $50.

Most urban areas have doorstep mail delivery. My older house in Seattle has a mail slot, as do the houses of friends who live in Detroit and Dallas.

Suburban areas are typically classified as "rural routes" so they're required to have mailboxes on posts out by the curb. These days, a "rural route" is basically anything that isn't an older neighborhood inside a larger city.

One can rent a locked post office box at the post office and use that for sensitive mail. From what I've heard, getting a PO Box is one of the first recommendations a lawyer makes to anyone going through a divorce. :)