American justice is bizarre. It seems so dependent on the prosecutor doing the "right thing" it makes you wonder why they bother with a defense team, judge or jury at all. Just let the prosecutor decide who's guilty!
/s (but only slightly)
So many cases are pled out these days (98% at the federal level), I doubt more than a tiny percentage of defendants are spending anything like $100k.
In addition, prosecutors are presumably held to a higher standard than defense lawyers, since they are state employees and are bound to act in the public interest.
We defer to the process for a reason. And human nature being what it is, that process is built on a presumption of innocence.