I am familiar with that link.
Even at this stage of the global economy, collapse or not, it is all getting a bit problematic. Shortages of some medications, fewer generics, most production overseas, and I read recently that even common medical supplies, like tubing, are mostly being manufactured abroad.
My husband tries to stay 2-3 years ahead on his personal meds. Otherwise, we have med staff/clinician friends who are stockpiling some injectable antibiotics and other items. So far, they say they have been able to work around the shortages and, of course, they are knowledgeable about substitutions. IMO, they know what is most stable and, as important, which antibiotics, et al, are best for what. From what I read and have learned otherwise, it is important to know which antibiotic to use for which sort of infection. Then, there is knowledge if dosage and side effects/interactions.
That is a lot of knowledge that is not that easy for the layperson to assimilate.
I purchased a physicians desk reference book and a nurses guide to drugs based on the recommendation of a nurse friend. I also have numerous other medical references. My goal is to have a basic level of knowledge myself and supplies for most basic problems. Perhaps if its something serious there will be someone around who can use those items to help.
As you say its unrealistic to develop this level of knowledge as a hobby.