In part, it is a version of the sunk costs fallacy at this point, and indeed has been for rather some time.
The majority of people consciously need to believe that all the rubbish that was imposed on them, and that they imposed on themselves, was for some purpose. Hence they prefer to believe there was some point to it all, the alternative being both to admit they themselves wasted great time and effort on something utterly pointless, and that the authorities were not honest in what they told them and forced them to do. I can see why they would prefer that, 'ignorance is bliss' after all. To use two other famous quotes:
“It's easier to fool people than to convince them that they have been fooled.”
"The bigger the lie, the more people will believe it."
In concert with that, the media and the government and the 'public health experts' have to continue to go along with the narrative for all the same reasons. While we appear to have a largely docile population, I'm not at all sure these institutions would survive admitting 'well, we wrecked the economy, imprisoned you in your homes, kept you from seeing loved ones when they were dying, stopped you seeing your friends, prevented you doing your job or continuing your business, forced you to wear a piece of cloth over your face, and caused a vast amount of physical and mental damage - and actually it didn't achieve what we said it would. Oops, sorry, silly us'. Certainly they don't deserve to.
So, we're in a very nasty stalemate, where I suspect most of us now know these things aren't true, at least subconsciously, but no-one in authority dares to admit it.