If I remember correctly, when Provigil became generic, they bought the company producing the generic form. They also slightly changed the drug and patented a new form as Nuvigil.

Last year, I asked my physician's assistant (I have never actually met my personal doctor) for a prescription and he told me that he didn't believe Provigil/Modafinil was even made anymore and tried almost emphatically to get me to take Nuvigil instead. I said no and that I'd try anyway. It was available and my insurance covered the Provigil ($750/month).