There’s some fuzzy logic here. Popper did not (as the author in the link alleges) assert that being falsifiable makes a theory scientific. He asserted that a theory that is not falsifiable is not scientific. That is quite different.
And the idea that theories that are proven wrong because their predictions are proven false nevertheless do not die is also wrong. Reconstructing a theory to produce a different prediction and thus avoid the falsified prediction is not keeping a theory alive; it is creating a new theory that is falsifiable and testable. The original theory did die, killed by failure in prediction; the new theory must stand the test of science regarding a new falsifiable prediction.
The fact that the new version of a theory, which has been adjusted to accommodate the past observations that killed the original theory, now conforms to those observations after the fact does not constitute corroboration. Predicting the known past proves nothing, it is the price of entry; failing to predict the known past is lethal. A new theory must account for the known past before it can be taken seriously enough for its future predictions to be tested.