The appearance of this skin failure appears to be very similar to the skin failure on the SWA B737. So, I will based my comments on the SWA B737 and allow you to determine if they have an merit to this event.

The skin in that area is made using a bonding process to join two layers of metal. To reduce weight, a process is performed to remove metal from the inside layer of the skin section. If you saw the skin section from the inside, you would see something that looks like a window shape where the process had removed material. Through pressurization cycles, the skin became fatigued and eventually failed. There are now several good comments on the Aviation Herald. Go back there for a better explanation.

Is this AA or Boeing? No, it's everybody. All airlines have old planes - well not every one but certainly many. Airbus does things in their designs to reduce weight and there are similar potential outcomes. Everyone involved is aware of the problem and working hard to mitigate the risk. I think they no longer use the process used back when this B757 was built.