I'd really think carefully about why you want that degree.
> But then I look around and see the cool jobs in 3D graphics, in distributed systems, in machine learning, or other "hard computer science" fields, and it feels like I will never be qualified without a graduate degree.
Why do you feel that? What signals are you reading? Does this feeling apply across the board, or only to one or two of the fields you listed?
> What should I do?
Your title suggests that you may equate "credential" with education. I would take a serious look at that because it's far from a universal view. In fact, it may be the thing that's really holding you back.