Another explanation for these numbers is that prosecutors are also resource-bound and risk-averse and prefer to go after cases they are almost certain to win.

Another explanation for these numbers is that prosecutors are also resource-bound and risk-averse and prefer to go after cases they are almost certain to win. There are, of course, exceptions of all kinds, e.g. https://en.wikipedia.org/wiki/Weev https://en.wikipedia.org/wiki/Weev.