Regarding your first point, the likelihood of a given infectious disease propagating is partly related to the susceptibility of the population. That’s what makes a
novel coronavirus so much more likely to become a pandemic.
We know, for example, that cross-immunity from other coronavirus strains do provide some level of immunity to SARS-CoV-2.
Another area of study is how decreased exposure to diverse set of microbes can result in increased incidence of autoimmune disease, and asthma.
While one angle to reduce the spread of disease is to prevent exposure, the other equally important angle is to avoid infection even with exposure (immunity).
I’d be very cautious about recommending population wide masking for extended periods. Our immune systems function by being constantly exposed and tested, and the system can break down if it isn’t provided with a diverse set of challenges to strengthen and build up immunity.
For your second point, I strongly agree that western medicine is particularly inept at providing care beyond treating acute symptoms, particularly chronic/sub-chronic conditions that tend to describe “how we all feel” and that don’t come with a definitive diagnostic test to reference in an insurance claim.