Countries are updating their defenses all the time.
They thought they had it all under control. They didn't. Learn and evolve. They didn't prepare for a small group of powered assassins hijacking a plane, killing a bunch of human passengers, wearing the skin of one of their own and skydiving at ridiculous speeds. Like you said, they messed up big time and I find that more relatable than having it all figured out.
Somehow they knew wearing pieces of Domino would keep them undetected. I hope there isn't someone on the inside leaking this information.