So far the playbook seems to have been:
1) Flatten the curve: Use lockdowns, masks and social distancing measures to maintain a situation where hospitals can still cope. This is not a one-time goal, it's an ongoing effort: As long as there was no vaccine, "no significant transmission right now" does not mean everything is back to normal - because if measures are lifted, transmission can quickly increase and become critical again.
2) Because the situation in 1) seriously sucks for everyone, try to come up with solutions to end the pandemic permanently (or at least make it permanently nonthreatening for the health system so we can leave "pandemic mode" and treat it as an ordinary disease). So far the most obvious strategy for this is vaccination - hence the increasing push to get everyone vaccinated.
3) Evolutionary pressures on the virus might cause the vaccines to become less effective. This unfortunately calls into question whether 2) is really able to bring an end to the pandemic. If this is really the case, then new plans are needed, such as boosters, new vaccines, I don't know. This stuff is currently being figured out.
1) and 2) does not seem like "moving the goalposts" to me. The goals were the same since the beginning of the pandemic, though of course the situation and circumstances were changing (you can only keep up a lockdown for so long, vaccines changed from "vague hope" to "viable strategy", etc)
3) is a new development that was apparently somewhat unexpected (I remember the virus was being talked about as relatively mutation resistant, which evidently wasn't the case.) - but this was simply new knowledge and new developments that might require a change in strategy - the overall goal to get out of this mess (by either eradicating covid or make it nonthreatening) did not change IMO.
Of course if this goal turns out to be permanently unarchievable, the goalpost shifting might start...