Consider a toy model with just 1000 double (64-bit), or 64Kb parameters. If you're going to randomly flip bits over this 2^64K search space while you evaluate a nontrivial fitness function, genetic style, you'll be waiting for a long time.
I agree if you approach it naively you will accomplish nothing.
With some optimization, you can evolve programs with search spaces of 10^10000 states (i.e., 10 unique instructions, 10000 instructions long) and beyond.
Visiting every possible combination is not the goal here.
Consider a toy model with just 1000 double (64-bit), or 64Kb parameters. If you're going to randomly flip bits over this 2^64K search space while you evaluate a nontrivial fitness function, genetic style, you'll be waiting for a long time.