People in the film industry from the President of Fuji to people close to inside sources suggest that 98% of the film shot was color negative. As film crashed from 1 billion rolls, it seems to have settled around that remaining 2% (that's us); around 20 million rolls.
Wallendo suggest that many of the cameras using this film were plastic point & shoots and, I would add, throwaways. Available used cameras might easily have reduced by a similar factor.
For sh*ts and giggles lets assume that, based on a peak of 20,000,000 cameras sold per year in around 2000 to 2003 reducing to less than 100,000 per year. Graphs show a drop of about 20% per year. Crunch those numbers and you get something in the neighborhood of 70,000,000 now-used cameras in that time. Let's assume that there were another 70,000,000 that have survived before that. Total 140,000,000.
IF we apply the 98% figure used in film we get about 3,000,000 used film cameras. I know that this is coarse but even if I am off by 50% the range is 4.5-1.5 million used film cameras.
Next, 3,000,000 divided by 350,000,000 Americans is about 0.0085 cameras per American. California has about 40,000,000 people let's multiply that by 0.085 and we get 342,000 used cameras in California. Using the same method NY has about 170,000 cameras, RI has 9,000, Ohio about a 100,000.
I know that the camera market is world-wide but I cannot find a number that I can use due to demographics. Say that there are 7.6 billion worldwide which for 0.0004 per person. That takes California to about 16,000, NY to 8,000, RI 421, Ohio to 4600. Suffice it to say the numbers have to go down.
I know these numbers are guesses from existing data and industry judgements. Also this assumes that all of these cameras are working. But, now, we aren't thinking about 1 to 2 gazillon or "beaucoup". All of a sudden the idea of a concrete and understandable number is more real. YRMV.