2. There aren't even any autonomous UAVs right now, why do you think you will be able to make one that can also autonomously evade a missile?
2. Because it seems well within our capabilities to do some basic missile evasion AI, that's just a small subset of the challenge of making a fully autonomous UAV. You need to identify the missile and its trajectory, identify its flight and kill characteristics, and then identify the various actions you could take and evaluate their likelihood of successfully evading the missile. Then you carry that flight plan out. Rinse and repeat until you're no longer in danger.
1. We should make a drone have the same flight performance capabilities as a fighter jet, which will make it cost more money.
2. We should spend even more money to create an AI system with the exact same capabilities as a trained fighter pilot. Probably not an easy feat.
I'm also not advocating for a completely autonomous drone, just saying that automatically flying a plane to evade a missile doesn't seem terribly difficult, as far as AI problems go, and the amounts of money thrown at these sorts of things are absurdly large.