What you describe is exactly the same as genetic algorithms (also genetic programming) or artificial life (Alife.) If you are interested there is a lot of information about these things available on the internet and plenty of implementations you can experiment with. And it does work to do amazing things. The problem is evolution is slow. Incredibly slow. It just tries random things, it takes awhile before it finds something that actually works. You say that nature is more efficient, but it's not. Not at all. It's simply had way more time than humans, and it has population sizes in the billions (way more for some species.)

But with the same amount of resources, human engineers are way better at designing things than evolution. If you give humans enough time, we can figure out how to make intelligence, and we can probably do a way better job than nature. At worst we simply need to reverse engineer how nature did it, at best we find an even better way.