My research was done a long time ago. I understood Ritalin to have mild neurotoxic effects, but Adderall et al to be essentially harmless. Do you have a source for the benefits giving way to problems long-term?
Regardless, your overall point is interesting. Presumably, these drugs are (ridiculously tightly) controlled to prevent society-wide harm. If that ostensible harm isn't reflected in reality, and there is a net benefit in having a certain age group accelerate (and, presumably, deepen) their education, perhaps this type of overwhelming regulatory control is a mistake. In that sense, it's a shame that these policies are imposed federally, as comparative data would be helpful.