You could do this without taking away the Mayan bonus; just give larger amounts when fewer resources are affected (e.g. food lasts 25% longer for one civ, stone 30 for another, etc). I’d rather give weaker civs more/better bonuses to compete with the top civs rather than just neutering every great civ bonus. Obviously balance is important, but I don’t necessarily like the idea of subordinating everything to it, and cutting everything great down to match the lowest common denominator. If the balance maximalists got what they wanted we’d likely have very bland, muted civs differentiated only by small, weak bonuses. Some people are already calling for the Mayan res bonus to be reduced to 10%, which would be almost unnoticeable beyond the Dark Age food boost.
To reiterate my earlier point, “balancing” civs exclusively or mainly by weakening them or recycling old bonuses is both the laziest and least fun way to go about it. Sure, sometimes the nerf stick is needed, but it’s best used with a light touch (See: Bohemians), and IMO there’s a better argument to be made for a net improvement of the weaker civs, then a net worsening of strong civs.