We can cut the cost down a little bit with cards that put the Cactuar directly into play like Dramatic Entrance or Chord of Calling and since those are instants, we can surprise our opponents by casting them right before our turn and attacking for 10000 immediately
Thus, people made decks out of a Mewtwo, a trainer card that reshuffles their discard pile into the library, and 58 energies, and then simply waited for the other player to run out of cards
A lot of players' intuitions are so poor that they boil it down to tournament viability only, but it goes way beyond that
This combo can actually work to mill out your opponent at times as well
Kuja, Genome Sorcerer // Trance Kuja, Fate Defied Rarity: Rare TYPE: Legendary Creature // Legendary Creature SUBTYPE: Human Mutant Wizard // Avatar Wizard CMC: 4 Mana cost: USD: $1.52 EUR: 0.87 TIX: 0.02 EDHREC RANK: 3296 (3/4) At the beginning of your end step, create a tapped 0/1 black Wizard creature token with "Whenever you cast a noncreature spell, this token deals 1 damage to each opponent." Then if you control four or more Wizards, transform Kuja