Well stated and pretty much spot on, with one exception...
The notion about "Programmers who are good program all the time, even in their spare time."
It has been my personal observation that this period of "Programming is the only thing worth doing with your life" (And yes, I know I am paraphrasing this in an unkind interpretation of what you said, I'm not doing it to be mean though, I'm doing it to illustrate a point) is true, for the first 5 to 7 or 8 years of a programmer's career. The reason seems to be that the deep fascination with what makes programming interesting as a career, continues to hold them even in the evening hours when they are at home. When not actually programming, they talk about programming, or programming problems or some aspect of computers and computing technology, when they can find friends to talk about it with, that is.
However, the basic drive behind this seems to be finding out as much as you can possibly find out about your chosen field or niche within the field. After that time period, though, something interesting happens. The MYSTERY of it all, starts to fade. You begin to see patterns in how things work, and similarities in how things are done, or are implemented, or can be implemented. Other interests start to take hold and after a while, family life starts to become important as well. At least, for a well balanced human, it does.
And that, I think, becomes my major point. The kinds of programmers who live eat breathe and drink programming, non stop, past this time period, are RARE, and usually are not well socially adjusted.
This is something that I think is not accounted for when interviewing more experienced software engineers. When looking at the scads of job openings for folks with 3 to 5 years of experience, your methodology and assumptions should work well, however, when you are looking for that really senior guy or gal who has been doing this for over 20 years, then the methodology, in my opinion, will not yield to you the best results. ie. teasing out the best candidate from the stack.
As an aside, I once told this to a young friend of mine who I met in college. I had already been programming for nearly ten years when I returned to school to get my bachelors in CompSci. I was always fascinated with just HOW MUCH he would go on and gush about computers, tech, sun workstations, sgi's, their hardware, their software, how to program them, linux and unix tricks etc etc.. One day I smiled and said to him. "I'll give you 5 to 7 years, and this utter all consuming fascination with computers will tone down to seeing them as nothing more than tools." He denied it, vehemently, he would NEVER have computers be something so mundane! It was, about 7 years later that I got an email from him where he told me "You were right." He's a googler now, and was one of the lucky ones who was in early, pre ipo and can now retire if he wants to. I myself tried getting into google, but made some mistakes in the interview process, trying to be 'clever'. It backfired, but that's okay. And not once did they ever ask me anything about what it is I do, or what I do best, or what I was interviewing for, board bring up, device drivers and kernel porting. Things which I'm very good at and have done for over 25 years.
Anyways, just my .02, your mileage may vary!
Sincerely,
Richard Dorfner