I tend to think that in a lot of ways, COVID was the perfect storm of just lethal and transmissible enough to be a legitimate public health crisis, but just not spectacular enough to engage everyone’s worst fears and paranoia.
I mean, if it had the exact same transmissibility and lethality, but did so through some much more visible and prominent mechanism- say violent and uncontrollable diarrhea, people would have not have claimed it was “just another flu”. The same if it was more lethal; if more people were killed by it, or if it was more uniformly lethal, people would have been concerned.
Combine that above with the high prevalence of asymptomatic transmission and the fact that for the vast majority of non-elderly people, it doesn’t amount to much more than getting sick for a week, and it’s the perfect storm for a lot of resistance on the part of the population.
Personally, the part I can’t quite wrap my head around is why asymptomatic transmission seems to be such a difficult concept for people to grasp. It’s like they can’t conceive of being a carrier of a disease without actually having symptoms yourself. I think that’s a big part of the issue- that’s the main cause of all the anti-mask stupidity that the GOP glommed onto, it’s a big part of the whole “open up now!” mentality, etc… People can’t get it through their thick skulls that just because YOU aren’t obviously sick, that it means that you can’t transmit it to others. THAT is why you wear a mask, not necessarily to protect yourself. THAT is why lockdowns were necessary; if it was something where everyone who got COVID had fever and/or was violently coughing or something, self-quarantine would have been much simpler, and people would have policed each other- people coughing would have had to go home from work, not be allowed into stores, etc…
But the asymptomatic transmission is the stumbling block; they can’t wrap their head around that and what it means, or they’re too damned selfish to put that ahead of their own desire to go out to eat or to a movie or whatever for 12 months.
Without all of those factors (extreme unlikelihood to kill non-elderly people, mild illness in most non-elderly people who show symptoms, and a high prevalence of asymptomatic transmission), it would have caused a lot more concern. But those three kind of self-reinforce, and cause people to dismiss it as “just another flu” or whatever else. The one I’m hearing now is 'Well, it’s going to be endemic, let’s just get back to the way things were." as if somehow it has run its course and nothing can be done.