THAT is the key to all of this—money. If the loser pays or the “over zealous” prosecutors can be held accountable in some way, our legal system would change over night! Right now, they throw any and everything to see what sticks whether warranted or not. And the defendant pays and pays and pays. It’s whoever has the taller stack of cash that wins, even if they lose.
It’s unlikely the forefathers foresaw the courts turning into great money engines for lawyers, as I would see it. That fact is what finally goaded the Supreme Court into requiring public defenders.