As CPU excess increases, I guess I've always thought that eventually code blocks could be grown using genetics inspired algorithmic processes that could just try everything possible until something works well.
You are underestimating the rate at which the number of possibilities to be searched explodes exponentially. Read the paper on Denali, an optimizer that conceptually tries all possible instruction sequences to compile a piece of a program optimally. Even though they used sophisticated pruning techniques and state of the art combinatorial solvers it didn't work for anything beyond a couple of instructions (less than 10), and AFAIK nothing practical ever came of it. Say you can currently successfully synthesize instruction sequences of length 6. The thing with exponential growth is that even if computers became a million times faster, then you might be able to achieve instruction sequences of length 9, not of length 6 million.
To some extent this is already done in a process called "Superoptimization"[1]. In that case, though, correct code is used as a rigorous functional specification, and the Superoptimization process will replace segments with shorter or faster opcode sequences with identical side effects.
