Ultimately the prosecutor should then go to jail for say 10x the time. Maybe that would make prosecutors less zealous?

AFAIK, only one prosecutor in the history of the USA has been jailed for malicious prosecution or intentional fabrication of evidence. And in this case there was no intent (that we know) to convict an innocent person, just wild incompetence, so likely just a stern talking-to from the head prosecutor is all they get.