Even if this minority gets away with continue driving without a license and wont get punished, you still save many lives by taking the vast majority of drunk drivers off the road. That alone is worth it.
Rare to see random checkpoints, and generally rare to have non-automated “mobile” enforcement of traffic rules in Europe (in my US, Canadian, French, German and Croatian driving experience).
Heck, in France most collisions don’t even involve police while they’re generally a mandatory report in US/Canada.
If you get a DUI in Europe, you were probably a bad driver on top of being over the limit.
Many drivers think that the police will get involved in every car accident, and when two cars have a little bump, people will stop and get out to "preserve the evidence" for the investigation into "who is at fault" that they expect will soon commence, but when the cops get there (because of the traffic jam) they just confirm that nobody is injured and tell the people to get their cars out of the street, and exchange license and insurance information.
Often police make you go to them. Tow trucks aren't supposed to bring unreported collision vehicles anywhere but a police station.
Cops here do like to take the interaction as an opportunity to issue a ticket, such as "improper lane change" or "careless driving" (which can be another "hit" on your next insurance renewal in addition to the "hit" from being assigned fault).
source: got summoned into court because the physicist who crashed into me tried to fight their ticket. They lost. My work treats this like jury duty and pays me, but I didn't realize until months later they took it out of my vacation. Grrrr.
The USA has IMO a terrible system which punishes DUI drivers through the justice system regardless of if they caused any harm. This leaves people with pretty shitty lives and prevents people from calling the police on DUI drivers. They can still drive shortly after though.