I've read a small portion as well.. bits regarding access to credit / finance / consumer banking are particularly salient, as are those regarding the state of inner city schools, and a whole bunch of other factors.
Citing "laziness" is really the easy way out -- clearly your job and my job are more "lazy" in some senses than being, say, a day laborer. So why can't the day laborer move up easily? A whole bunch of reasons, very few of which have to do with laziness. You can try to cite intellectual laziness if you want, but these guys didn't exactly get a chance to take AP calc senior year.
Regarding your ex, yeah, immigrant groups do have extremely high mobility and that's one of the great things about America is our (waning) receptiveness towards immigrants. But they're an extremely self-selecting group. That's not "average".
Regarding you and me (assuming you're a reasonably successful developer in some fashion), the major financial differentiator between us and our peers is the fact that tech work pays really well right now and doesn't necessitate a bunch of grad school debt. If I wasn't born on an automatic trajectory for college? And was the same guy in every other way? I'm at best a 50% shot at becoming a developer.. probably I'm working at Safeway instead. And doing a good job at that job, because I'm not lazy and that's my nature.
You can claim to be substantially more "fit" than me if you want.. and hey, maybe you are -- but if you're going to claim "gumption" as opposed to "born lucky" as the major reason you are where you are, then statistically, you're probably just underestimating the luck.