In both fields, there are immense bodies of literature, the most advanced of which are so arcane as to be indecipherable to the masses.
In both fields, there is a tiny sliver of the population so educated and advanced that they can reasonably claim to be among the world's best.
Which is to say that the available evidence suggests the two fields have similarly difficult learning curves.
Your statement would thus only be safe to say if you believed the average chess player were about as smart as the average dog. So I'm going with yes, since my dog beat me two out of three the other night.
Isn't it safe to say that regardless of how much training many people do to become a GM, they have about as much chance of achieving it as a dog who studies as hard as possible will master physics?