hey I know its been awhile but I found the answers to the freezer bag wrapped cuts of meat mystery, found it in a butchers manual. its called wet aging.
its a commercial form of aging the meat, they hang the beef just long enough for rigor mortis to set in, then fast process and freezer bag the cuts so that the meat breaks down in its own juices and tenderizes inside of the bag.

the reason they do this is because they can process alof of sides, like any assembly line, in and out in a couple days instead of the 2-3 weeks of hanging in the cooler. dry aging shrinks the meat but bag aging does not, so essentially they get a side cut and out the door in a couple days without the freezer costs and also charge that extra 30% that would otherwise be lost to the dry aging process.