A - If the population growth of the last 40 years is scary to you, I have good news. Population growth has peaked and flat-lined. If we don't increase our fertility and/or immigration rates, we are going to enter a long period of population decline, similar to what Japan is facing
B - In 1980, with 28 teams, and 45 players on each roster, NFL players represented 0.000554575% of the population. In 2022, with 32 teams, and 53 players on each roster, NFL players represent 0.000510224% of the population.
Top tier football talent level does not rise linearly with population (especially when immigration from non-football playing nations is a significant portion of that growth), but for the sake of argument let's assume that it does.
If we calculated the theoretical number of NFL players we would have, should we increase to 1980's level of 0.000554575% of the overall population, that would give us a total of 1,843 players. Given the current 53 man roster, that means we should have enough players for 34.8 teams, 2.8 more than we currently have.
Given the non-linear nature of talent growth, I would say we are pretty much spot on. ¯\_(ツ)_/¯