That's because "destroy a gene" is not a treatment. The process of finding a molecule that inhibits the action of the gene, is not rapidly metabolized by the bo

That's because "destroy a gene" is not a treatment. The process of finding a molecule that inhibits the action of the gene, is not rapidly metabolized by the body, is capable of crossing the cell membrane, and doesn't kill people at the same dose as it has its effect takes a while. You have to try a lot of molecules to find one that satisfies all these requirements. There are efforts to speed up the early selection process, such as using computational chemistry approaches to compute which molecules can "dock" with a protein's active site. This is hard though, because proteins & small molecules are not rigid, so it's much harder than just doing a jigsaw puzzle in 3-D. I'm sure robotics is also being used to speed up the initial drug screening, but I know less about that. Also consider that there's no way to tell the long-term toxicity of a drug except by running a long-term study. Basically, my dad (who works as a pharma researcher) told me almost exactly what you proposed: it takes 10-20 years to develop a drug and bring it to market once you have a target to develop against.