Morkus from Orkus
What an absurd argument. You can't share with yourself. If something is yours, it's ALL yours.In a solo game a single person is both the DM and a player, therefore its still a shared authority between the players and the GMs.
The solo DM/player creates a different circumstance where there really is no player as the game defines it. It's effectively just the DM running NPCs through a dungeon.