While you will need to activate it every turn for this to work, once you have an established board state, that's not a big ask whatsoever
The Motherlode, Excavator Mono-red just lacks the energy production to fuel The Motherlode, Excavator, and its a pretty weak payoff anyway
The first player is usually heavily advantaged in modern Magic, and designs like Lonely End and Sylvan Smite give the second player more stabilizing potential when playing from behind
Goblin Tutors Goblin Matron, Goblin Recruiter, Moggcatcher Goblins have been a force to be reckoned with in Commander for over a decade, traditionally headed by cards like Krenko, Mob Boss to make dangerous swarms or Purphoros, God of the Forge to inflict massive damage to the table in and out of combat, but plenty of other color combinations and strategies are quite viable too