well you would think after 30,000 tests in phase 3 that would be unlikely
The phased trials don't really have anything to do with that. Viruses mutate-- inevitably, always. Which is one reason why even the flu vaccine is only 25% effective (or less) some seasons, even when they toss multiple strains into the flu vaccine.
We have not once, ever, developed an effective vaccine for any of the numerous coronaviruses we've faced in the past, coronaviruses that have been with us for centuries or even millennia. There are some different reasons for that, and one could be that we've never
tried this hard and applied this level of resources to it, in all of human history. But another factor is that coronaviruses are tricky bugs.
So yeah, I think it's entirely possible and even likely that we won't ever have an effective vaccine for this, and that it will take its toll on humanity as a
novel coronavirus, and that eventually it will have done all the damage it can to the most vulnerable humans, and will no longer be novel and will retreat to being just one of many well-known coronaviruses that harm a certain percentage of the global population every single year.