This is a very bold and dangerous statement you are making. Like I said, the over-representation of Asians is a complex issue, you can't start categorizing one group as being more motivated than another without appearing linear-minded. I tried to use a cultural explanation, but in retrospect, that thought process itself is flawed.
There are lazy Asians, and there are hard-working Asians. There are lazy African-Americans, and there are hard-working African-Americans. There are lazy Hispanics, and there are hard-working Hispanics.
Ok, so if there are lazy Asians and hard working Asians etc. then how come there are more Asians and Indians in medical school than blacks or hispanics even though there are far more blacks and hispanics in this country? Why are we considered "overrepresented" and what's leading to that consistent succcess? And why are there so many ethnic Jews who go into law/banking/medicine/the most prestigious professions as well? What is tied with prestige? Money.
Basically we have affirmative action policies for blacks and hispanics because they are lagging behind severely against the Asians and Indians (and Jews to a lesser extent because they're "Caucasian" really).
So again, itt's because of money. Money is what impels people to do things. It's what drives people to go through the B.S. of memorizing SN2 reactions and going through 8+ years of mental torture. Of course you can say that you love medicine, but if you haven't worked a full time job like Mister T said, and you haven't been in medical school, then how can you know you'll like it then? A lot of premeds with noble intentions ended up realizing in medical school that it was NOT what they expected it to be and if they could do it again they would not have.
And there's nothing wrong with going into medicine or anything really for money. It seems that fundamental gist of what you seem to be making is that because people go in for selfish reasons that it's a bad thing. If that was the case, then communism and socialism would be a much better system (one only needs to look at the defunct Soviet Union and even China which has opened its markets for investing over the past decade), but what we've found is that capitalism and private enterprise tends to create the most economical efficiency and productivity in an economy which basically translates into a better quality of life for everyone, and that's what counts, no?
I have personally experienced, not just from my family (my mother would telll me to go into medicine is an honorable and noble thing to do from an early age as it was her dream and her mother's etc) the push to go into medicine, but almost every premed that was Asian or Indian was going into it for the very same reasons.
Of course, there are some who are not, but they're definitely the exception to the rule.
Btw, I read the medical school forum and residency forum here on SDN a lot, and its funny how a lot of the students always discuss the "ROAD" specialties" and how desperate they are to get into them, and they are always freaking out about ObamaCare health care cuts and how much they would lose from them. What does that show you? And if you don't believe me you need to only pay attention to how the AMA and doctors are reacting to ObamaCare (it's going to be the end of the world apparently)
People's opinions seem to change drastically once they are in medical school as everyone in the end cares about their personal BOTTOM LINE.
But yeah, read up on supply and demand, that's all it is really. The rest is just misguided idealism, inexperience, and ignorance.
We're better off not worrying about what reasons people are going into medicine, but for the sake of argument, they're not sticking through with them because people love being in the OP room for 80-100 hours a week for minimum wage, they know that there is a light at the end of the tunnel; a very bright light, mind you.