* The challenge then they often face in accepting XP/Agile is their own conflict-of-interest. *
You see, XP and Agile are brutal if you are lazy or if you are (or have become) mediocre. There's no place to hide in XP- everything is exposed. You can't create the anecdotal "job security hacks" so that you can't be replaced- because there are others in your team who know your code and can replace you if you're not pulling your weight. Or if you're a contractor, you now risk being caught for overbilling if you don't have "velocity" commensurate with the hours you're billing.
I speak, of course, from my experience as a programmer.
But more currently, I speak from my experience as the founder of a startup- as the employer, the product manager, the project manager, the requirements analyst and ... the customer. The engineers who "get it" are those who are passionate about "doing the right thing", are hard-working, and definitely above average, if not smart. The smart engineers who failed despite our best efforts were typically either washed out senior engineers (unwilling/unable to learn anymore) or had the fatal combination of inexperience & intransigence.
Succeeding in XP is not easy. It requires intensity and focus.
And merely "working hard" is no substitute for productivity.
There's no place to hide in XP.
"Well, it may be all right in practice, but it will never work in theory"
- Warren Buffett, on the attitude of his alma-mater Columbia University towards his method of investing.