It's easy to blame the executives for their meddling and they're often very much to blame but it's also something which is a bit more complicated than that, I think. While executives have always been the easy scapegoat, there's a long history in both movies and video games of the "out of control auteurs" who really are obsessed with their vision and go nuts once they're no longer reigned in. John Romero is a particularly infamous example for the fact, once he didn't have any controls, created one of the worst video games of all time.
There's also the constant conflict between the fact developers routinely don't actually want to make the game which they're commissioned to make. While not a gaming example, one particularly infamous example was the development behind Terminator: Salvation who were outraged when the developers "ruined" their production by changing the ending, changing the focus on the characters, and refusing to go with their "bold new direction" for the franchise.
Which was, to clairfy, killing John Connor and attaching his skin to the face of a Terminator replacement who would lead the resistance from that point on.
Being the artist is no guarantee, basically, of being good.