Is the DM not playing a game?Playing a game
In my opinion, no. He is adjudicating the gameIs the DM not playing a game?
RAW and my experience say that you are wrong. If all he was doing was adjudicating, someone else would be making the adventures and playing the NPCs/Monsters. Adjudicator is just one of the hats this player is wearing.In my opinion, no. He is adjudicating the game

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.