Hmmm... this is interesting.
First of all, ADHD, at least at the symptomatic level, does indeed exist. I know! The symptoms of it basically equate to an overactive/restless mind. It is very difficult for me to concentrate on tasks, and the less interested I am in them, the more difficult it is. I mean difficult as in the following scenario, which plays itself in classrooms from the time I was 14 until right now:
1. Go into class and sit down
2. Teaching begins
3. I begin to get distracted with other thoughts, though I'm fighting to concentrate on the task at hand
4. I begin to fidget
5. I suddenly (VERY suddenly) become extremely tired
6. I spend the rest of the classtime time using every ounce of willpower I have to stay awake
It's not a discipline or willpower issue. This even happens (though to a lesser degree) in classes that I am 100% interested in.
Regardless of this, I had a miserable time in high school. Actually, it sounded a lot like Ustwo's public schools experience. My folks couldn't send me to private school and didn't have the education to teach me much at home. I found that by 7th grade I knew subject matter better than MOST of my teachers, and by high school the AP/Honors content I was learning was at a level I had already learned. I dropped out of high school my senior year, got my GED and went to a VERY good engineering school. The kicker? My GED and ACT scores were high enough that not only did I not have to go through the "mandatory" probation time at OU as a GED-bearer, I didn't even have the "mandatory" freshman probation before being allowed to enter the School of Engineering. I was admitted my first semester.
I am socially well adjusted. I have a lot of friends that are all pretty different (I'm often the 'link' between disparate groups of friends). Sure, some are geeks, but many are not. I am married to a wonderful woman. I have two great sons. I have a good job. I can work with people very well. I can outsmart them if I need to, but generally can adjust to talk on anyone's level, low or high, based on the person I am addressing. *shrug*
So, back to the OP. Are young men less motivated? Yes. But I see it as a primarily American cultural issue. American culture breeds laziness and ineptitude, from vastly overused social programs to vastly underfunded education and extracurricular programs. Hey, you want to be a fat sack of shit with 20 kids and a meth problem? Here's some free money to live on. Hey, you're a brilliant student and an amazing musician? Well fuck off... we can't afford good teachers and your school doesn't have a music program anymore! Gee, I can't imagine where the problem lies. As for the sudden increase in females being marketable. Well, that's still backlash from suffrage and ERA-era buildup. Women can NOW do things that men have been allowed to do forever. They're taking advantage of it. Good for them!
My wife will have her degree before me, despite being 6 years younger. I still make better money than she likely would after she gets it. I also sit on my ass at a desk job all day, and when she is finished with school she'll be chasing kids on the playground at school. *shrug* Sometimes it's a matter of aptitude for different things. There are more geek guys than girls, or more specifically in the geek category that tends to be a money maker (IT). My wife is a band geek. It's hard for a band geek to make good money. I'm a computer geek. It's easy for a computer geek with no degree to make GREAT money. It's a subculture thing at that level.
I know this is sort of a jumbled rant. Hope you all followed. Let me leave you with another thought. Why do I believe this is American? look at other countries, western and otherwise. Take Japan for instance. Fast food is hitting HUGE over there, and video gaming is as big or bigger than in the States. However, they have more discipline, better education (with much MUCH more emphasis on education) and culturally kick our asses in such regards. It's not young men, it's under-challenged, over-pampered, lazy American young men. :-|