...an interesting side (or maybe main) issue would be comparing cost of being a "serious" amateur from 50 years ago to today, over the course of a year. (You might even have some stuff (pictures, equipment, lab stuff) from that time period to illustrate that would encompass "developing and printing" of photos in the mix.
Today, once you have a good camera and a lens, your only further investment is an editing program (I would believe that nearly every home has a computer for other uses).
With the 1970 technology, you had to send the film away (or, if luck enough to live close to a drug store take it there to have it developed) the wait for the prints to come back.
If you did it yourself, you could rather quickly develop black & white film, but needed time and chemicals and a dark room, and the cost of an enlarger and paper and chemicals for that.
If you wanted to shoot (and process) in color, there was also the cost for consistent temperature equipment for the film and print developers as well as the chemicals, enlarger and paper.
Today, there is instant gratification/ability (chimping) on the scene to see what you got and ability to immediately change settings.
AND, OH YES...today you are not being limited to 36 shots per roll of film. Now, you can do 'bursts' of almost limitless shots.
Computer editing is much wider-ranging than the very limited 'creativity' in the developing/printing process of film. Today you got editing programs which can drastically widen the exposure/color elements as well as edit out the encroaching telephone pole.
Then you have cropping -- and seeing it all in regular (not negative) viewing.
The ability to share photos, even by internet to a dedicated frame anywhere in the world, is there today. In 1970, again you relied on the mail to show grandma how the kids have grown.
And, if you throw in drone cameras, adaptors for telescopes, remote (game) cameras and even "Ring" doorbell cameras, you get a wider range of what "photography" means today.

Oh, and did I mention video built into most digital cameras today? No more grainy pictures of "Uncle Ned" waving at the camera in 16 fps, and waiting for film to come back, then editing, then viewing, but only when everyone was gathered because you had to set up the screen and projector. Of course, on the bright side, there likely would have been popcorn, too...

And, today, you can have it included with your personal phone/notebook/computer, too.

Has any other "everyman" endeavor expanded so widely????

All that and probably cheaper today when compared to "1970 equivalent dollars."