I'll go from the top down but the last statement you made pretty much sums it up.
My experience has been that there is rather strong negative correlation between brilliant programmers and people who put a lot of effort into their appearance.
Not really asking for a "lot of effort" on a day to day basis, at least it doesn't seem like a lot to me. It could be relative. But this is just the opposite side of the divide and relevant to the whole issue. To come off as a "good developer" to you I need to look homeless. I like wearing the button down shirts that I do. It makes me "feel" more professional and gives external form to my internal ethos.
Hmm, I honestly always felt that programming and a lot of other technical fields was the last place where you weren't required to be ambitious and career-oriented and could come by just on technical skills.
Depends, honestly, on your career goals and field. You still need to be able to play the people game, usually, if you want to advance. Or be stunningly brilliant. Piss off the wrong person and you will halt. Sucks, but true. One of the most painful lessons I had to learn, actually, was that skill/ability alone won't cut it except along fairly narrow tracks.
Wouldn't you rather have someone who's just ... good rather than someone who respects the environment and the interviewer?
No, frankly. I need people who smoothly integrate into the environment. I'd rather have someone who is 80-85% and integrates well into the culture and environment rather than someone who is 100% or 110% but is a constant trial for their coworkers. The increase in effort dealing with that person combined with the morale reduction they can cause is just not worth it.
Quite frankly, I can't know if I respect someone when I just met that person. That assesment takes time.
True but it all starts with a first impression. I might only have thirty minutes or an hour for the first interview.
Well, then it becomes part of the functioning of their job of course and an entirely different story.
Yup.