>>53733976High usage =/= centralizing. Great Tusk, like Lando, has no recovery, gets worn down easily over repeated usage, and is particularly weak to special attacks. Gholdengo can OHKO it if it doesn't have any SpD or HP investment.
252 SpA Gholdengo Make It Rain vs. 0 HP / 0 SpD Great Tusk: 331-391 (89.2 - 105.3%) -- 31.3% chance to OHKO
That's not a specific counter, that's just a regular ass Pokemon. You can blow up Great Tusk quite easily with just powerful special attacks let alone Water/Grass/Ice/Fairy/Psychic type attacks.