It has nothing to do with getting people who don’t want to get the vaccine to change their mind. It’s all about getting those who say they will eventually get the vaccine to come in. In recent polling 57% of people said they had gotten the vaccine (lined up with CDC numbers at the time of the poll, we are up to 60% now), 20% of people said they would never get the vaccine no matter what and 23% of people said they were not opposed to getting the vaccine and would likely get it eventually but were in no hurry. So the things like the donut offers are not intended to convince the 20% in the not getting it no matter what crowd. They are mostly a lost cause. The offers are a way to get the people left who say they will get the vaccine eventually to come in sooner than later. In other words not all of the unvaccinated adults are anti-vaxx a large number just haven’t gotten around to it yet. Hard to believe for someone who fought for an appointment as soon as they were eligible but not everyone thinks the same.