One should draw a distinction between bad faith actors and good faith actors. For bad faith actors you are correct, but you could say the same thing about a lot of controlled substances. They (stimulants) are at least as controlled as benzos if not opiates. After all there is no objective test for chronic pain either from what I understand. For good faith actors I think there are perhaps the correct or at best too many burdens already, as given by the large percentage of people who are under-treated.