Gotta do something with the outdated expensive equipment.
Check it out:

What is the 1033 program? Well, it’s a law that says excess equipment from the Department of Defense can be transferred to local law enforcement. It started in the 1990s. Since then, $4.3 billion in equipment has been handed over to local police forces.

These military equipment exchanges will reach record highs this year (via WSJ):

How the program works: When the U.S. Department of Defense has surplus gear — either because the military has upgraded to new gear or because it’s no longer necessary — they put it on offer for U.S. law enforcement, with the majority going to state and local agencies.