I watched a lot of the early tv conferences, and the Sage members (Whitty, Valance et al) were always very open and matter of fact about the probability of a long period of rolling lockdowns based on the Imperial modelling. They also repeatedly cautioned that it would be a long road with any vaccine not being an immediate magic bullet, and predicted 2+ years of disruption with winter restrictions possibly carrying on for a few years.
It might be that lots of people didn’t quite take this in at the time, or couldn’t quite process it psychologically, or have forgotten it when vaccines came along, or whatever, but the scientists and medics absolutely were open and factual about this from the start. (Tory politicians may have been giving other impressions, but the long slog of getting through the pandemic was emphasised by Whitty etc. from the very outset, to be fair, and I’m not his biggest fan….)