I have always said - If a prosecutor thinks he has enough evidence to charge someone with a crime:
He should be required as part of his job to take the case to trial - period.
Many defendants (guilty and innocent) have public defenders that pressure them to take a plea bargain and knowing enough about how the system works and the inadequate defense they have, they decide to take the plea bargain.
Those with money, are often strained to the point of bankruptcy before a case even gets to trial and when faced with the option of a plea bargain often take it because they have an attorney charging between $240 - 300 and hour and they lack the resources to survive a trial. Or worse, they go to trial, while expending all of their available resources and have a hung jury and/or a mistrial and are facing the same charge again at another trial, only having spent most of their money during round one.
Most convictions occur at the point of jury selection. Both the defense attorney and the prosecutor if each one has enough experience in courtrooms knows what the outcome of a trial will be based on jury selection. Which is why so many prosecutors that are absolute cowards (once again regardless of whether or not the defendant is guilty or innocent), will put a plea bargain on the table after jury selection if they think things are not going to go their way and/or even prior if they lack the balls to even go all the way.
The plea bargain system is a way for criminal courts to abstain from their duty to bring someone to trial, while offering something just to get a conviction, although with a lesser charge and not as much time. It in and of itself is criminal.
www.chasingjustice.com
Kerry Max Cook (see above link) spent 23 years on death row in a Texas prison and prior to an appeals trial, the prosecution offered him a deal for credit for time served if he just plead guilty.
Cleared a few years later due to DNA evidence and prosecutorial misconduct which included suppressing evidence and ignoring links that led to the person that was actually guilty of the crime.