First I have to admit that I have not gone through 149 pages of posts on this subject - it is obviously as very active topic! So I may be repeating the obvious, and if so I crave your tolerance.
On the subject of diseases that have caused major loss of life, our species has been ravaged frequently with various plagues, pandemics etc. right back into prehistory.
In those very early days the population was smaller and travel less likely to spread the disease, but the lack of any understanding and countermeasures meant that diseases often ran unchecked and created mass localized casualties. As our population and interactions have increased so have the levels of transmissions. Certainly the last 100 years have yielded several mass diseases of one form or other whose spread has been enhanced by mass movement (as in the spread of Spanish Flu through the return of servicemen from WWI) and other forms of mass transport (particularly air travel) that have made us and our bugs far more mobile. Countering that we have increased our technologies and organizations, but each new disease takes time to recognize, isolate, contain and create treatment.
There is a conflict between the interests of the authorities, in wanting to isolate us to prevent the spread of disease (and as disease spreads it modifies), and the business community that wants to continue to operate and generate income and wealth. This is not an easy conflict to resolve as it demands that the population accept and trust the advice from experts and are prepared to support what would be considered highly restrictive (and to some draconian) measures to buy time to allow the developments of treatments.
We have a socioeconomic system world-wide that depends on commerce and the transmission of goods and services. It takes a degree of social responsibility to cease activities and lose financially when those we engage with closely will suffer for the benefit of people we don't know. This lack of empathy is particularly prevalent as our population grows and we engage with large numbers of people. Professor Dunbar, an anthropologist, evolutionary psychologist and a specialist in primate behaviour came up with a number of people to whom we can generally relate and recognize (we don't have to like them but we recognize them) and that is in the range of 150-200 people - roughly the size of a pre-civilized village. The closer the relationship the smaller that number becomes. Conversely, as we widen the numbers of people, so our engagement decreases - in fact we spend time in cities avoiding eye contact because we have no contextual relationship with strangers. One impact of this is a decrease in sympathetic behaviours and that results in a survival conflict where we look after our own interests first when threatened and show less remorse for large numbers of casualties.
One of the biggest challenges that has always needed to be addressed is knowledge. By that I mean developing the technical, scientific, and medical knowledge to determine the source, countermeasures and treatment of disease. The other is social knowledge. In a crisis, if no authoritative and reliable information is forthcoming, it leaves an information vacuum that is quickly filled with rumour, political agendas and attempts to leverage the situation for material benefit. In this century that has been turbo-charged through the world wide web and social media.
More and more people are getting their information from totally undocumented sources that proliferate all sorts of theories, projections, accusations and treatments that have absolutely no scientific rigor or truth. Sadly, people are trusting these sources more than the experts in the scientific, academic and medical communities; often because these falsehoods fulfill their own opinions and biases, and they avoid those sources that might undermine their preconceived beliefs. Such behaviours have been turbo-charged by political attempts to undermine science and the 5th estate as a conduit for reliable information, or to stifle the media from coverage at all. This is not limited to one country, it appears in many countries and societies around the world.
Things are further complicated by our geo-political profiles - and these vary dramatically between nations. It's much easier to control one's borders when living on an island nation (such as I do in NZ), where one can shut physical access to the rest of the world and then deal with the internal implications of infection. Most countries share a land border with at least one other and many are fairly porous - by which I mean determined people can pass through between countries without control. This is even more so where there is conflict, such as in the African continent and Middle East, a situation that is further exacerbated by the existence of massive and poorly resourced refugee camps, characterized by large populations in close proximity.
So what is the point of all this? Simply put, many of the elements I have described are stacked against us. The frequency and ease of transmission, disease modification. Our own behaviours: distrust, propaganda, political, economic and social agendas, biases and focus on immediate agendas are challenges that make this disease harder to fight. It may take many months for effective and trusted medical countermeasures to be available and until then we will have to do all we can to stop the spread and evolution of the bugs. That will conflict with our fears and desires to hold a normal life and our fear of change. It seems likely that for the foreseeable future we will live in a world of change, like it or not. Seeking a pre-emptive return to normality when we have not got control of this runs the risk of repeat waves and new variants that will defeat the very outcomes we are seeking. And a lot more people will die.