shifting baseline syndrome

Etymology
Coined by scientist Daniel Pauly, in reference to generations of scientists treating the successively reduced fish populations of their own time, rather than the earliest recorded fish population levels, as the "baseline", so the "baseline" kept shifting.

Noun

 * 1) The tendency of each generation to consider the state the environment (or by extension any other thing) was in when they grew up or first examined it to be its natural state (baseline), normalizing changes made by prior generations.