Perhaps one of the reasons social-host liability hasn’t caught on yet is that the “duty” one is expected to perform is onerous.
Should one of my guests insist on driving home drunk, I have two choices: either take his keys by force, or call the police and have him caught.
In the first case, I could get badly hurt — and, if my friend is only slightly over the legal limit, the combined physical harms to me and my friend are probably much higher than to the sum of the expected harms to all drivers on the road.
In the second case, my friend will lose his license, and perhaps his freedom. The penalty for getting caught driving drunk is much higher than the harms resulting from the individual infraction, as a deterrent, required because of the fact that so few drunk drivers are caught. So this is not something I would do to a friend. A stranger, perhaps, but not a friend.
The fact is that social hosts faced with an intoxicated friend who insists on driving have no reasonable recourse.