It's not like photographers demanded Flash as a presentation layer from the begininning. Obviously, they saw something in it that would allow them to control how the user views and interacts with their work while eschewing alternatives.
These are people who have invested not just thousands of dollars on equipment, travel and education, but who have also dedicated their lives and sometimes livelihoods on their art. To ask them to further invest in the ever-changing landscape every time a technology falls out of favor may be too much for them to bear. Just like a simple camera and film, Flash has been there, relatively unchanged, for many years.