Oftentimes the government drops the case. When people get convicted for things they did on Tor, and don't settle, the government often drops the case so they don't have to reveal how they got information about activities on Tor.
When Germany, which doesn't play by the same rules, got DiDW and then Boystown, that was quite revealing on how authorities can break Tor.
That's when the government is the one bringing the case to begin with. The issue is, if the government e.g. kills your spouse, why should the perpetrators get off scott free because the perpetrators want to keep something a secret?
Imagine the public tried to do that. Sorry, IRS/DoJ, the defendant is refusing warrants and subpoenas because it's a secret and without that you can't prosecute them.