If somebody predicted in 1998 that an event would happen by 2020, and by 2021 it hadn't happened, but by 2025 it does, does that invalidate the original claim ? Many of the predictions on ExtinctionClock may perhaps have had overly pessimistic 'deadlines', but the predicted outcomes have not been proven to be false, they may well be merely later in arriving than originally presented.
For each of those predictions, have you any evidence that totally debunks them ?