I agree in not putting all the hope in a vaccine. I mean, I think there will be one or multiple, but we have no idea how effective it will be. It would be nice to get one that is wildly successful but it would be wise to keep expectations in check.
Look at what has been learned in the past several months. Not rushing to intubate people even if their oxygen levels are shockingly low, a couple preexisting drugs that reduce hospital stay/mortality to some extent, etc. Even among the people who have comorbidities/are older, they are in a better position to survive than they were several months ago. And in a few more months, perhaps they will be even more likely to survive than they would be right now, before any potential vaccine.