And there's also the issue of the time it takes to design something and get it approved. If it's something of your own, you can just add more memory and be done with it. For a system like this, management has to decide it needs to happen, and they may have to get approval from government regulators before they can do anything. Then the engineers make the changes to the design which in the case would probably be just a higher capacity memory chip. But then the system will need to go through significant testing to be sure the new chip can survive all situations it might need to. Then government regulators will have to review and approve the design, and with the speed government takes, that may take a while. Finally, once that's done, the airline can begin to retrofit the new system into planes. By that time, it may have been several years and the new system is already obsolete and way behind the current iPod.