When does it make sense to start bribing people to get the COVID vaccines?

Demand for the COVID vaccines in the USA is apparently beginning to slacken: the seven-day rolling average has fallen below three million, and there are many parts of the country where there is essentially no wait time to get an appointment.

At present, about 53% of all adults have gotten at least one dose of the vaccines, and 35% are full vaccinated.

So what happens a month from now, when, speculatively, 35% of adults are still completely unvaccinated and demand has cratered?

Up to this point, government policy in regard to the vaccines has been completely voluntaristic: there have been essentially no carrots or sticks deployed, beyond the obviously very important one of making the vaccine itself free. But if, say, a third or more of the adult population has to be both bribed and coerced to get vaccinated, it seems like we should start doing both things as soon as it becomes evident that it’s necessary to do so.

As for bribes, the obvious thing to do is to pay people to get vaccinated. Just spitballing here, but 20% of American adults equals about 50 million people, so if you can get the adult vaccination rate from 65% to 85% by paying holdouts say $250 apiece, what is that, $12.5 billion? That’s nothing! Why wouldn’t you do that?

OK a few scattered millions of people who were already vaccinated will whine about how UNFAIR this is. Pay them too to shut them up: it’s still a drop in the bucket.

Of course this means we’ll probably have to bribe Billy Bob and Lurleen to vaccinate their kids against COVID when children’s vaccines are available, but we can fall off that bridge when we come to it.

I’m sure there’s a bunch of very good and complex reasons why this is a bad idea but I can’t think of any.