I think a bit of the cause of this, in my part of the world at least, was the whole Herd Immunity concept that was latched on to and fixated on beyond all else. Added to that, when the initial vaccine rollout caused the death rate to drop infection numbers were ignored and all attention was then turned to getting back to 'business as usual', even going so far as to demand businesses recalled office workers to return to their blocks even if working from home had worked for them and their employers.
The vaccines not granting sterilising immunity, something I didn't know about and I don't doubt most people didn't even have a concept of before this pandemic, really came out of left-field and knocked all that faith in herd immunity on its ass. It didn't exist, not with naturally acquired immunity which waned too fast and at least not in this generation of vaccines which as stated didn't lead enough immune systems to a point of being able to sterilise - for a large part although they protected the individual, they could not protect the society.
The problem, at least where I am, is that once a strategies foundations are sunk into the ground and a response is built off a concept of Herd Immunity, we are stuck with that being the foundation all other actions branch off. Even though Herd Immunity it is now known to be a myth and won't happen, it's still the crumbly rotten core at the bottom of the wall with all the other bricks piled up upon it. The lack of precaution, the encouragement of spread, the continuing lackadaisical response to events even now, proceeding in a reactive manner rather than a proactive manner, is all harking back to that first fatalistic set of descensions to just roll over and let it wash over us.
If one were to compare it to a war with an invading force coming in to a country, the leaders and decision makers basically threw open the gates and lay flowers and loaves of bread on the road to greet the advancing tanks with smiles and applause. The metric for failure was the health system being overwealmed, the only thing that prompted action was attempts to avoid overloading a system which had been neglected to whither for decades.
And don't get me started on the "There is no evidence for Precaution X so we won't even try until there is established evidence, but no one is going to fund that research so pass a hat around if you want us to look into it but don't you dare do Precaution X personally just in case because it might do you more harm than good, yes technically we don't have any evidence for that statement either but we're not going to spend any time to research that... just trust us it'll do you more harm than good don't do it and if you do don't come crying to us about it". Absurd when you look at it from a distance, isn't it?
Perhaps the war analogy is a bit too over the top of a way to word it, but in essence the battle was over before it had even begun. At least, that's how it looks where I am. How'd it go your end?