You're right. I've noticed many doctors tend to first prescribe drugs that reps are selling and are "hot" on the market (ever wonder where they get all those Viagra and Zoloft pens?). Doctors are humans so are capable of ignorance and laziness like the rest of us. But I don't want to get too into that right now lol.
But yes, I have heard of Desoxyn being prescribed. My doctor has prescribed it before for narcolepsy patient(s). I don't think he does much lately as there are some newer, more fitting substances for treatment. He's pretty cool and one of the better informed doctors I've seen. He's been the only doctor knowledgeable enough to cut through the BS and prescribe me Xyrem (GHB) which has been a great help. Which is pretty cool because now he has had great success using it with other patients.