I mean, if you've had a few drinks and get in your car, you're not going to be automatically stopped and ticketed. Instead you're weighing the risk that a cop is going to just happen to catch you.
If the laws are changed so that driving drunk isn't presumptively a crime, but rather that if you're in a crash and found to have high levels of alcohol in your blood, then the crash is assumed to be your fault and will have extremely high penalties, then the difference is just in the details. You'd be balancing a lower risk, but of a much higher cost.
That might not work as well because of some people having poor skills at discounting future risks, but it's not obvious that's the case. It deserves further investigation.