They say that if a frog is placed in boiling water, it will jump out, but if it is placed in cold water that is slowly heated, it will not perceive the danger and will be cooked to death. It’s a metaphor that speaks to the inability of people to react to significant changes that occur gradually.
Of course change in photography has been going on since it was invented, but I can remember when the “water first started to warm” for me. It was when I was handed a Kodak NC2000 in the early 1990’s to photograph a Presidential debate in Lansing, Michigan for the Associated Press. It was the start of digital photography for me. (Rob Galbraith has an excellent essay on the NC2000 here.)