Vinblastine was discovered when they were testing a folk remedy for diabetes and found cytotoxic effects so it was completely tangential to the study’s goals, and in modern parlance, an instance of a “task failed successfully.”

Paclitaxel was discovered literally from a random spray and pray scan of plant samples from every taxonomic class, here I will quote a literal sentence from a review: “ Barclay collected T. brevifolia, an evergreen, apparently because the strategy was to collect at random. Not much was known about the tree. It belonged to the genus Taxus...” (https://www.acs.org/content/acs/en/education/whatischemistry... )

So I still believe in what I said, which is random screens or complete serendipity often has been the best ways to get t a lot of our therapies, though I’m not advocating for more of that necessarily.