You can have what I would consider deep knowledge of a system without the ability to manufacture it or modify it. For instance, we have pretty deep knowledge of how the sun or other stars work, but we can’t even begin to dream about creating one, or controlling one.

In the same way, we know a lot of how biology works. Obviously nowhere near all of it; but we are far beyond just scratching the surface. It just turns out that modifying a working complex system is pretty hard.