The story about picking an unpopular disease that was easy to test reminds me of why Monsanto went with glyphosate resistance as the first serious GMO target: Trivial testing.

Back when Monsanto started that kind of research, the technology to modify a plant's DNA, and checking the quality and location of the modifications were extremely crude: you'd see the modification inserted into hundreds, if not thousands of locations at once. It was definitely going to make the plant worse at growing at the beginning, and require a lot of work to use traditional breeding to improve the seedstock again. But glyphosate had a huge advantage: Testing whether your new GMO plant has your genes properly activated is trivial. plant all the modified seeds as you can, wait a few days until you have leaves, then spray the whole thing with glyphosate: If the DNA didn't make it, or it's in a place where it doesn't get expressed enough, the plant just dies. No need to use a chipper and spend a ton of money sequencing and checking the specific location of the insertion.

Today the speed and price of genomic pipelines is such that one can attempt a lot more complicated things and get results without risking so many failures, but if you make detecting failure cheap, you end up ahead anyway.