I see your 3 scenarios like this:
(1) It doesn't appear to have had any real effect in terms of hospitalisations or deaths in an around Bolton - please correct me if i'm wrong there, but I haven't heard any news to suggest it. I'd wager if there was going to be a material effect on these metrics, we'd have seen signs of it by now, given elapsed time.
(2) This will never go away.
(3) This will also never go away.
There may be outbreaks, indeed I expect there to continue to be moving forwards.
I do agree that we can't know what the medium and long term holds, but then that's the same for every disease, and maybe it's just me, but i'm not one to get over concerned with ifs and buts. I'm not worried that the measles virus will randomly mutate to become resistant to extant measles vaccines, and i'm not worried about this because the results thus far give me no reason to be.