First of all anything that is widely adopted will be used for crime. That's just human nature. Tor is widely adopted right now but there have been alternatives like Freenet for example.
So the choice is either anonymity and crime, or no anonymity at all. And crime won't go away, it just won't be able to use an anonymous channel for communications.
And it's not like criminals are getting away with it by being anonymous either. If you go on tor to commit crimes then you will be hunted down by the international police. And if you commit heinous crimes against children then you will find no refuge. That's not a good life to live. Odds are you will end up in prison sooner or later.
So the choice is either anonymity and crime, or no anonymity at all. And crime won't go away, it just won't be able to use an anonymous channel for communications.
And it's not like criminals are getting away with it by being anonymous either. If you go on tor to commit crimes then you will be hunted down by the international police. And if you commit heinous crimes against children then you will find no refuge. That's not a good life to live. Odds are you will end up in prison sooner or later.