The answer here is that it is much, much easier to build a functional deck with all oddconverted mana cost cards than it is to build one with evenconverted mana cost cards
Kroxa, Titan of Deaths Hunger This escaping elder giant is a daunting Rakdos card
Most Used Format Non-Meta Decks Public Decks 136 Tournament Decks 0 Total Copies 285 Avg Copies / Deck 2.10 Main Deck 94.7% 270 copies in 135 decks Extra Deck 0% 0 copies in 0 decks Side Deck 5.3% 15 copies in 13 decks Similar Cards Cards with related names, effects, or gameplay patterns
Older formats have the Urza Tron lands, Eldrazi Temple, Mutavault, Dark Depths, and the list goes on
So, setting things up to make the Zombie God just wont happen in Limited without some incredible luck, so well disregard that