That's a really oversimplified view. The truth is beyond a certain point no amount of "theorizing" is enough to overcome the sheer computational power of programs. AlphaZero just took advantage of recent advances in neural networks and GPU hardware to achieve a better tradeoff between hard rules and heuristics than Stockfish. Both of them are probably Pareto efficient in some sense, and barring some insane undiscovered loophole in the rules of chess it's unlikely that any human can come close to beating them.