I have ADHD and take mixed amphetamine salts so I'm not homeless.
18mg of methylphenidate is on the lower end of "middle" in terms of dosage. I can relate to the "drugged" feeling and euphoria and that's a common complaint (that they feel like they're wired or that the euphoria is gone after the first week!) within ADHD communities. However, it doesn't last after the "break-in period," where the side effects dwindle and so does the euphoria. All you're left with is focus in pill form. It also should be noted that amphetamines et al. affect neurotypicals (relatively) differently than those with dopamine/norepinepherine disorders. While neurotypicals commonly (from first and second-hand accounts) note that they feel high, those with ADHD feel like they're "normal."
If that's too broad and indescriptive, then I point to the account of a small subset of people who only found out they had ADHD from experimenting with stimulants. They find their life no longer becomes a Sisyphean task and they can function like a normal person. Whereas neurotypicals might start picking at their skin or masturbating for hours, those with ADHD will finally clean their rooms or make that phone call they've been meaning to make for the past 2 years.
As to your belief of the "well-meaning parent," I have to disagree. I have been around poor families, stable families, and rich families, but most parents don't have the first clue of what ADHD really is, even less what an "amphetamine" is. Or even how to use thoughtfully use Wikipedia and the internet to answer their questions, instead of differing their thinking to, seeming, authorities. It's akin to asking the box-spring salesman if your bed needs a box-spring. The box-spring salesman will tell you all of the benefits in easily digestible, and deftly crafted, sound-bites. And then you will accept his proclamations and move on with your life, believing he knows best. The same is done by the majority of people who are in contact with drugs and supplements. Even more so, parents who are too busy/exhausted/inflexible by virtue of the mental capacity degradation that comes with years of not having to use much thought to get by, i.e the bulk of parents.
Most people do not do cost-benefit analysis, but a subset of "involved" parents will allow their children to be medicated (whether rightfully or wrongfully) to let them get a step-up over their peers. To this I agree, but I don't believe it's as common as your argument makes it out to be. To the statement after about "the cost of not drugging," I agree, but like with last statement, it's not common among parents.
To the rest, I have to say, in my opinion, your statements reek of neurotypicalness. Atleast, not of someone that has a disability that separates them from other people. This is not an insult, but an elucidation on the disconnect between yourself and other people's mindsets. People are very common and predictable, but if you're among them you likely won't see how. One of these similarities is that they believe everyone thinks like them. For you, it might be a more rational approach. For someone else, it might be a more feelings-oriented approach, that mimics rationality by appealing to the homeostasis of one's emotional state.
It's hard to tell where someone is going when you're all moving in the same direction. Now move yourself to outside the crowd. You can see all the little peculiarities of everyone's movement. Like a school of fish, they're all synchronized, but those peculiarities set them apart. With major disabilities, you're forced outside that school of fish, and destined to stare at everyone, instead of moving with them. Overtime, all the different combinations of moves have been played out. All the idiosyncrasies have been enumerated, and there is nothing left to deduce, but that most people are too wrapped up in going forward that they never step back and take a breather. To unplug from the global consciousness and just watch the synapses of other people fire. To peer take a look at someone similar so you can recognize your own shortcomings.