I'm not denying that you can abuse prescription stimulants by taking large doses to get high but most people aren't taking 10-30mg a day and experiencing meth like feelings of euphoria. Especially with extended release formulations. It's also much harder to maintain the regular abuse of a prescription stimulant without resorting to illicit acquisition since most psychiatrists avoid prescribing high enough doses to make that feasible.

I can't speak for every person who abuses prescription stimulants but I've met people that do and they always had a meth or other addiction in their past and were either buying from dealers or seeing multiple doctors/pharmacies. It's been a while since I've run into someone with that problem though so I don't even know if the latter strategy is effective anymore. I assume the feds maintain some kind of database these days.