Unfortunately the carton dates only indicate when the items were packed into those cartons, they may well have been in storage before being packed into the cardboard cartons. If you get the names of the producers off the cartons then you can usually find out a little more, if the carton is generic and does not carry the name of the producer then chances are it's been repacked somewhere along the line. Cardboard cartons don't hold up well in high humidity storage, so anything that has been stored has to be repacked when it comes out of storage....unless it was originally packed in breathable plastic....look at the little punnets of berries as an example.
I used to work as a fruit picker (and packer) on my school holidays so I know from my own life experience (rather than docos) that the fruit is picked and goes into the carton then onto the back of the ute or truck and off to market.
Our farmers don't really have the money for very sophisticated storage systems and they generally want it off the farms and sold so that they can pay the bills.
If you actually take a moment to look at the labels you will see that they nearly always have the name and address of the supplier (even the black pallets). As far as I know this is a legal requirement. I never worked anywhere that didn't slap a sticker on or have a custom box with a date space that we filled in in texta. Why not try ringing some of our farmers and asking them about their storage systems - the number is often right there on the box. Our farmers are people too - not they're faceless forces of evil.
I have no doubt that there is some very old fruit out there but you don't need to know much about fruit to spot it.