Any relevant research in Motivation? I came across another reference to how CS education does not produce bimodal grade distributions etc. Also re-read some stuff about gender issues, that women are not mentored and supported and so on. I have no desire to raise those issues again. 

However, I do feel that there is some sort of difference in motivation. Not to do with gender, race, income, etc, but just as a human trait. We have the OCEAN traits in Psychology (Openness, Conscientiousness, Extroversion, Affability / Amiability, and Neuroticism. These seem to be universal. Is motivation something that varies among people? Can differences in motivation affect how hard they study, persevere, self-teach, find alternatives, and other factors that lead to success in studying and in the workplace? 

Does Motivation vary? (Not the actual question, just the premise.) 

Is Motivation what we need to focus on regardless of any other factors? (The actual question.) Three factors of motivation are Autonomy, Mastery and Purpose. I see those all as being self-defined, relevant only to oneself. 

I know that since I was a child, anything I chose for myself as my goal, whether learning about electronics, or resisting my schoolwork, I pursued with the greatest force and energy that I could rouse. Everything else was simply not important. So, when I went to college, I already knew I wanted to learn programming, nothing else mattered. I didn't have mentoring, I barely even went to office hours. I just did it on my own, which is what I did in all my pursuits of personal interest, like radio, or learning photography or whatever. So, I am at a loss to understand why college students do not know what they want to major in, or why they are not motivated to work on their core courses. Why don't they leave college and just do what they actually wish to instead? 

My guess is that because I was Introverted (one of the OCEAN traits) I preferentially chose tasks for myself that were intrinsically rewarding when pursued alone, and which could not be blocked by having no access to other people. 'Others' and their preferences were the block, so I "routed around" it. 

Please enlighten me. Maybe motivation is bimodal, and is the real issue underlying inequity, etc? if I understand other people better, I can do better.
Understanding people better can enable you to more effectively teach them.

Taken as axiomatic, this can be a helpful thought. It can also be a distraction. The value depends on how it's applied. When trying to understand "people", you can aim to understand people as a collective of unknown size, from unknown backgrounds, and unknown individualities; something you cannot ever "know" or understand. Conversely, you can aim to know the 35 students in your classroom, with backgrounds, experience, limitations, and gifts which you can know, and whom you can begin to understand. At least with respect to how that information affects their performance within your subject matter.

I have no links to research into motivation, and can only suggest that if any were found it would be inefficient to read it, or the conclusions drawn from it. The results would be extrapolations of an imperfect model using statistical analysis gathered by researchers with some pet theory to prove, or disprove. The 'repulsive' statement you found is merely one example of many which can be "concluded" from some observation. While, within the experience of the writer that statement might be true, it could be also be untrue in others' experience. What's left out of the statement are the conditions which define "fail", what consequences there are for failure, what is expected to be gained by success, and how much effort is required to achieve what "change".

If I will be passed over for a promotion unless I gain 6 inches on my biceps and increase my bench-press limit by 100 pounds, and the promotion has a net increase of 15% in pay, I'd personally be willing to "fail" rather than change. Given a different set of conditions, 3% pay increase for learning a new Java framework, I might not consider "failure" as an option.  (I don't know Java, so I'd have to learn that first.) In the second case, to me, the change is more desirable, even though the consequence of failure is one-fifth that of the first.

People, as an amorphous mass, can be classified, categorized, and "pigeon-holed" neatly by any study or research project. People, as one-on-one real individual humans, seldom fit into any neat "system," no matter how well researched, or refined it may be. If a system were ever developed that could classify people, manufacturing lines could be reduced to producing the one version that fit the needs, and wants, of everyone. We would have the 'one' computer system, with the 'one' OS that everyone could use to do everything they needed. The 'perfect' automobile could be made in the correct color, black according to the legend of Mr. Ford, and the Big-Four would be out of business. And, in your case, you could write to last, perfect, syllabus and lesson plan for each course you teach. (I'll not hold my breath for any of these things.)

Interestingly enough, I did have some college classes, and I somehow match part of what you described. I did not know what I wanted to major in. I never did manage to "focus" on the core courses. Nor have I managed to collect so much as an Associate's in anything, despite having nearly 150 semester credit hours collected. (I did manage to earn, by accident, a "certificate" for Linux Professional, which surprised me when it came in the mail after I failed to collect it from the office.) I've been connected to computing, and electronics, for decades, and will always be doing something within those areas. Yet I was not sure that should be my major. Perhaps it would be better to major in business, and use my computer skill within that arena? Of course, it didn't help much that I viewed computers as "fun" either. When ever I do "work" with computers it feels like being paid to play, and I almost feel guilty collecting the check.

The "motivation" you seek to understand exists in everyone. It remains individual as to what can activate, or trigger that motivation, or which subject(s) it might be applied to. The target of motivation may not even be a goal, it could be a journey. Some may be motivated to achieve some tangible reward, or to avoid some imagined consequence. Others could be motivated by the "rush" of doing something, or of experiencing the stillness of doing nothing. 

That you don't see, or recognize, the motivation of another does not mean it does not exist. "Absence of evidence is not evidence of absence." (And there ends a 3 hour tour into the rabbit hole of The Demon-Haunted World: Science as a Candle in the Dark.)