Silver nitrate has other uses besides making film and paper. It's not likely to become unavailable at any time. Prices will fluctuate, sure, but the silver nitrate will not likely ever be the bottleneck. Market dynamics are a different story.
Making film or a recording medium without silver...well, there's always digital. No other materials besides silver are known to be practical in image capture, so you're out of luck there.
Fortunately, there's no foreseeable end to film production yet. Enjoy it while it lasts.