Many people claim that the millenium bug (Y2K)was an unnecessary panic. The argument goes: "On Jan 2000, there were only a few problems attributable to the Y2K problem. Therefore the effort used to solve it were wasted."
As one of those who actually removed a Y2K bug, I know this statement is untrue.
A more detailed example is: "Companies who did nothing about the Y2K bug did not suffer any problems. Therefore effort to remove bugs were wasted".
The truth is that big software suppliers solved the problems; their customers did not need to do anything other than accept the routine updates which delivered the fixed software. So it is strue that many companies did nothing and suffered no problems, but it is not true that effort was wasted.
Is there a specific fallacy that describes falsely concluding that an activity was unnecessary because the activity successfully removed the evidence that it was effective?