Professional photographers don't get paid as much as they used to because photographs can be transmitted from place to place around the word at essentially no cost. And multiple copies of the same photograph can be used simultaneously by multiple users, in multiple locations.
Possession of a slide, print or negative no longer gives control over use or additional use of an image.
Naturally, this has decimated the prices paid for stock photography, as well as increased immensely the use of cheap stock photography where in the past custom photography would have been commissioned, but that only affects professional photography - a relatively tiny portion of photography in general.
Photography as a whole is much more vibrant, much more widely practiced, much more likely to be seen. Yes, the environment around it has changed but, at its core it is still energized.