The problem is, US lawyers are ridiculously expensive. I'm not aware of any other country where one court case against you can ruin you financially. So it doesn't matter if you are innocent or guilty, if you are charged, you've already lost.
EDIT: Why not make it a law that when you are found innocent then prosecutor's office should refund whatever it cost you to hire your lawyer?
EDIT: Why not make it a law that when you are found innocent then prosecutor's office should refund whatever it cost you to hire your lawyer?