I don't think that most crime will be considered more of a mental illness, unless we're willing to consider selfishness as a mental problem too. Serial murderers may be getting treatment, but a lot of crimes (especially white collar) happen out of plain old willingness to pursue your own interests at the expense of others. There will need to be a form of enforcement that will keep people in line - the will to game the system seems to be far too common to consider it as an abnormality.