Anybody being 'curious' about a yearly booster only needs one response.
Flu jab, has been yearly for how long, yet people still get flu. Weird isn't it this science/medical stuff!
There will be a point where it will simply become a case of getting it with, instead or an adapted vaccine that covers all bases (I am no scientist but the latter is the most logical, surely). It won't be mandatory but those in the high risk groups strongly urged to get it.
My work here do a flu jab every year, on site. Simply put your name down, get a time slot where you can stop working for 15 minutes. It doesn't even fell like you are wasting any time.