[sampo]

> no one could really explain why exactly they worked

Genetic algorithms work on problems where some subsets of variables are approximately separable (uncorrelated) from some other subsets of variables.

F(a,b,c,d,e,f) ≈ F1(a,b,c) × F2(d,e,f)

So if you have found a good combination or a,b,c it makes sense to try how it works it any promising combinations of d,e,f. Some natural world problems really have this property.