We are quite literally alpha zero ourselves. We developed chess by playing ourselves. I don't get what is particularly surprising that there are not infinite ways to play good chess?
Maybe for more complex games, example: economics. But chess is pretty simple compared to seven billion people going their own ways.
On the other side, AlphaZero and all the previous Deep Mind's AIs played some very different go than human players did. Every single move was not unheard of but they were dismissed by human masters as not good. The most noticeable contribution was the total change of how to play corner invasions. By looking at game records we can draw a line between pre and post AlphaGo. Maybe go is a little bit more wide than chess and AIs have more space to find novel plays.
We (humans, AlphaZero) are both distilling the rules down. Some rules are easily distilled (a queen is worth more than pawn) some are more difficult (mobility, knight vs bishop). I would expect the easily distilled rules to be discovered by both of us.
What I think would be cool is trying to distill or revise better guidelines from what AlphaZero does.
Human minds didn't evolve for playing chess. So there was a possibility that there are "hardware" limitations that prevent us from playng it the way it should be (give or take the inevitable error margin).
I suppose if AGI gets achieved then some of this will seem predictable in hindsight. But we don't yet know if it's achievable.