“Game developer” isn’t a full-time job, it’s just seasonal help.

Companies only need game developers during “we need to make a game” season. After that season is over they let most of the seasonal help go but keep a few for “the game will need patches” season. Once that season’s over it moves in to “sit back and count the monies” season, where game developers are totally useless because they’ve all been laid off so they have no monies to count.