I suspect people are getting addicted to them. Like needing their next fix. No other reason why anyone would get boosters
There may be a little sheer laziness. Or maybe path of least resistance. If people just do what they are told - get vaccinated, get boosters, wear a mask, social distance... They don’t have to think, they don’t have to take responsibility. “Hey, I’m following instructions to keep me and everyone around me safe!” Then they can’t be blamed if they or someone around them gets sick. “Hey I followed all the precautions, I’m a victim here!” They are being conditioned to obey without question, without pushing back.