It is amazing.
I had a roll of film that sat around for about 7 years and the photo quality was pretty bad. I was color, so perhaps that was a factor.
Indeed. Color film is organically base, where the older b/w film were silver (as I remember). Used to develop and print my own b/w many years ago. Was schooled that b/w was much more durable. Our color negatives and prints have faded over the years, but my old b/w prints and negatives are still solid..(40 years).
B&W vs. Color is a big factor for sure. But even bigger is the quality of the film and chemicals used in development.
Your early tintypes gave way to glass plates not because of bad quality so much as because oxidation caused the quality to deteriorate. The next big advance was paper film then, by the 1880s, roll film. Even then it took about 30 years to help photography to make the leap from the studio/professional market into the home/amateur market.
Great quality film from the World War II era was probably a combination of response to higher resolution demands to meet wartime needs and, at the same time, an attempt to slow the consumer stampede into the color market which really heated up after the war.