> You can't officially license an Adults Only game on most (all?) consoles
There are a bunch of PEGI 18 games on consoles. Call of Duty World War II, Farcry 5, Fallout 4, GTA5, etc etc - all of these are PEGI 18 and licensed for consoles.
Those are all M in the ESRB rating though (not AO). Despite the parallel in AO and PEGI18, they aren't really the perceived the same in the respective markets.
Best case study for this difference is the "Hot Coffee" mod for GTA: San Andreas. There was originally a very adult minigame in it but it was disabled; the "mod" simply enabled it. This caused so much controversy the game was re-rated AO by the ESRB and consequently pulled from store shelves until they re-released a patched version with the minigame removed completely.
There are a bunch of PEGI 18 games on consoles. Call of Duty World War II, Farcry 5, Fallout 4, GTA5, etc etc - all of these are PEGI 18 and licensed for consoles.