It's not going to be a pandemic, which by the word itself means "it infects everyone". We don't like "epidemic", because I guess it isn't scary enough, but that would be far closer to the truth.

Also, it seems to me that 75% would be good enough to stop a wide outbreak, since islands of 60%--where we would have serious death rates in the susceptible 40%--isolated in oceans of 80% or better, which would firebreak the disease spreading.

I'm all in favor of people getting vaccinated. I'm not, however, terribly troubled by those that choose not to. At least not yet. Your post does, however, raise the question of how soon I ought to start worrying.