Medicine Man [0] is a 1992 movie about a researcher who discovers a species of ant which has cancer-curing properties. As a teenager at the time I thought, "Why doesn't some pharmaceutical company simply test every ant species to find a cancer cure?".

Today my answer to my younger self would be, "Because there are thousands of ant species and the company couldn't patent its discovery, so there is no incentive to conduct such expensive research"

[0] https://en.m.wikipedia.org/wiki/Medicine_Man_(film)