If you had to have a computer for 20-30 years, you would definitely want to be able to load new data.  Even if we could fit all the current radar data into the computer, as weapons change we would need new data.  And there is much more to mission data than just radars.  You can’t fly around with all of google earth.<p>And this doesn’t even account for the general crappiness of military aviation technology.  People assume the latest fighter jets are cutting edge, but the F-35 technology is probably already 10 years old.  Flying F-18s from 2002-2012, the max number of GPS points we could store was something like 256.  We had “bricks” the size of a brick that could hold kilobytes.  We updated to cards that could hold a MB.  This is when thumb-drives where moving into GBs.<p>Cheaper, specialized aircraft, both man and un-manned is critical for our national defense.  Aircraft that are more expendable and can be upgraded with new tech quickly and at less cost.  The industry, however, just builds what they want and then the Generals and Admirals get board seats so everyone is happy.  When I left, the F-35 was pretty much considered a turd by most pilots, but a hand-full of senior leaders where pushing hard and based their careers on it.