Right. Criminal prosecutors, like many other criminals, are the product of their environment.
Yea, it always tickles me when people discover that every group with adverse incentives ends up corrupt. Almost _everyone_ is corrupt. It's rare to find a person holding a single damn principle, which is why incentive design is so important.
Conviction rates for one.
Does the prosecutor get to choose which cases to prosecute? If so if you're optimizing for a high conviction rate you should drop all cases except your absolutely most solid case. Then just ride that 100% conviction rate for the rest of your career while dropping all future cases.
Conviction rates don't exist in a vacuum though. If you have a 100% conviction rating but have only prosecuted one case, no one is going to care. The real key is to bring extreme charges against large numbers of people and then offer them palatable plea deals. You get a large number of convictions with little effort and the few people who risk going to court aren't going to hurt your conviction rate much even if they win.