I'll argue with the assumption that there is zero long term psychobiological consequences to exogenous psychostimulants (I personally don't buy this, but let's assume it was true). Increasing focus and task salience is only one of the many factors constitutive of human potential. They never give the answer for what to focus on, or whether a task is worth it or not, and rob the person of the opportunity for developing frustration tolerance. They turn people into indiscriminate doing machines, with little wisdom to guide it. Makes one think if prescription amphetamines being as widespread among plumbers as software engineers is truly a coincidence.
I will argue this is because our bioeconomics, our not wanting to do things is also part of our wisdom machinery. Having used for half a decade myself, I can spot some collogues who are on amphetamines; unnecessarily assertive, obsessed with orderliness of code, constantly in need of refactoring, huge bias for action with diminished wisdom to temper it (Well, also pees a lot.). There is a reason they are not being used by fighter pilots anymore because they can get too cocky and make decisions that kill their own.
No wonder everything looks like a good idea when your brain is swimming in dopamine and norepinephrine, but when everything looks like a good idea, how do you find what is the right thing to do in the medium/long term? Is that really the human potential? I would argue far from it. I think it is just enhancing the potential for a particular job description that requires you to sit on your bum all day and plumb boring stuff someone else tells you to.