It's an interesting theory and I relate to it a lot. Just ask my Mum. Every week I'm all "okay, so guess what I want to do with my life now" and she's all -->
I also relate to their cyclical nature, which is why I always try to leave an opening to come back to what I'm interested in at a later date, like keeping everything relating to the languages I'm trying to learn and storing my leatherworking tools safely until the compulsion hits again (rather than getting rid of them, like I did with a lot of my books before I realised I'd be interested in them again one day.)
Thing is, I'm already being medically treated for ADHD, but it's not making any difference to the number of interests I have. What it does help me with is being able to appreciate delayed gratification, put down whatever I'm intensely involved in and do that tax return or the washing or an assignment. It also helps to finish a project that I started with great fervor but have since lost interest in, (so I don't have to feel guilty about it later).
For a long time I also wished I could stick with just one thing, because, as you point out, I'd be freaking awesome at it. But I've come to realise that's just not my personality, and whether this is due to my ADHD or not I don't know. All I know is that if I tried to do one thing for the rest of my life I'd be miserable, meds or not.
In this way, I like to think of myself as more of a generalist than a specialist, but I'm a specialist at being a generalist and for this reason I can have incredibly interesting conversations with a wide variety of people, engage in a multitude of projects and have already done and seen more in my life before reaching 30 than most people I know will ever do and see in their entire lives.
The world needs a lot of different types of people, and if the ADHD meds don't help in tethering you to one special interest, I wouldn't be too upset....they'll at least help you do your taxes.