The distinction to make is that our ancestors did not have the population density we now face. Had they reached the number of people that live on the planet now with no mask, the consequences would have been devastating. That’s the whole point. Infectious disease has ever followed humankind into civilization and shaped the course of history. Wherever we dared to concentrate high-numbers of people, diseases appeared.
When we look at animal species, we recognize this phenomenon where a disease counters uncontrolled population increases. Animals who populate an area too densely may soon suffer from a contagious outbreak that persists until it no longer spreads effectively among the species.
Ultimately, you’re correct that our ancestors did not require masks to prevent these types of pandemics. They also lacked global trade, air travel, paved roads, and daily commutes. We populated cities with less density, and rural communities were far more common, with more people spread over more land.
This seems to be an argument for allowing a pandemic infectious disease spread uncontrolled. The economic state that it would bring would be far worse than many realize [1, 3,4]. It is also the case that a low mortality rate is a pandemic feature, not a comfort. Diseases with high-case fatality rates are much less likely to cause a pandemic for several reasons. We wore masks in 1918, and people raised many of the same objections, and we took many similar precautions to contain polio.
Polio has much more similarity to the behavior and implications of Covid than does seasonal influenza. Poliovirus spreads asymptomatically, and a minority of people experienced serious illness or death, but we know the disease today by its least common symptoms.
With every pandemic/outbreak, we see the alternative theories about the source and “motivation” for the crisis. When you read theories from other outbreaks, it’s striking how similar they are outbreak-to-outbreak  A quick search of the history of infectious disease in the United States shows the reality that truly there is nothing new under the sun.
Some quotes from 1918 case studies were so close to things said by people today that most would struggle to guess what year someone said it. Masks are far from feel good as they both reduce transmission such that semi-normal society can return, and they may also reduce the proportion of severe cases in the population.
Although we knew that the economic consequences of slow action would be grave, I believe it was not until July when we saw reports and studies from WSJ  and Goldman Sachs that we saw previously resistant decision-makers embrace masks. Perhaps more than testing or distancing, masks have the power to allow us to have a normal life.
I’m unsure what the last sentence relates to as the recommendations arose from continually reassessing the body of evidence, hence the requirement for adapting our position. We can decide as a society to leverage the advantage of evidence and save our economy, kids’ in-school education, and mental health, and join nearly every other country in finding our new normal, or we can refuse, clinging to a world that no longer exists, that got us where we are now.