Yeah. Actually the easiest part is making the art. And even that's only easy if you have a dedicated group of (hopefully good) artists. Programming and bug fixing is the monumental task that seemingly never ends. Not to mention sound effects, music composition, etc. All that stuff takes a lot of time, commitment, and talent.
Oh, and you also have to have a clear direction for the whole project, and a coherent idea of every scene and interaction in the game, if not an actual written script. Writing interaction descriptions is a whole other chore in and of itself. At IA we all pitch in on that front, but without a solid project director who knows what he wants, it'd never get done.