[kemiller2002]

If you think you are wasting your time, you need to leave. Three years is a long time to spend on something where you see little benefit. The question you have to ask yourself is: "What are you going to do with your degree after you graduate?" If your answer is, "I don't know," then it's probably time to quit and form another plan, and it really sounds like this is possibly the case. If you aren't learning from your adviser, that's three years of you falling behind all the other candidates who you are going to compete with to get the job you want.

Realistically consider for a moment how many people graduate with an advanced degree in your field vs. how many jobs there actually are.