Simple answer, "No". I know it won't stop everybody, as you rightly say somebody drugged up to their eyeballs won't care. That's the category of offender that should be removed from society permanently.
I'm not really thinking of murderers, crimes of passion or the one off, well planned crimes involving huge amounts of money.
I'm talkng about the sexual crimes, the small time crooks, hooliganism and the like. Crimes rarely committed as a one off. And committed by offenders who frequently escalate as they "get away with it".
Clear up rates have improved since Victorian times but the deterrent has been eroded. The deterrent may be different for different people but clearly six months inside or more likely community service isn't adequate.