If your game-theory is correct, we are dealing with a tragedy of the commons like game. These types of games have highly un-optimal Nash-equilibria. Hence, it m

If your game-theory is correct, we are dealing with a tragedy of the commons like game. These types of games have highly un-optimal Nash-equilibria. Hence, it makes sense to take collective measures to prevent that Nash-equilibrium. Such collective measures would either be 'a sense of duty' or 'mandatory vaccination'. People ignoring the first option are kind of asking for the second option.