I don't think you can solve complex problems and guarantee the solutions are easy to understand. (You've hit the nail on the head.) But you can absolutely sol

I don't think you can solve complex problems and guarantee the solutions are easy to understand. (You've hit the nail on the head.) But you can absolutely solve many complex problems without straying outside of the set of simple arrangements or simple configurations of purely simple solutions. It may still be hard to understand. It was probably hard to write, too. It should not be hard to refactor, if at all possible, when the scope of the problem has predictably changed later on.