The issues with rural roadside mailboxes isn't the box itself but the kids that seem to get some sort of twisted enjoyment in vandalizing them. While I haven't had to replace one lately, I've replaced quite a few over the years from getting smashed or teed off the post by kids with ill intent. I've had to replace the post a few times as well but usually, if the post get sheared off, there will be car parts nearby to attest to the damage.
2 years ago, had the box and post sheared off and the intoxicated driver crossed the road and wiped out the border fence at the east side of the property and ended up in the creek, State Police came and arrested him and had to have the car pulled from the creek. Tore up the mailbox, the post and fence line that I had to repair. Of course we slept through it all, we are sound sleepers....lol Liquid courage at it's best...