$10 billion for counter drone measures or drones that kill other drones would be better.
Let the Russians, Europeans, Indians, Middle East Muslims and the Chinese make attack drones (so early 2020s) that we can easily sweep from the skies.
Using a fighter jet worth $100 million to take out a $5,000 drone isn’t cost effective. Expensive equipment doesn’t win wars... Lots and lots of money wins wars.