A well-run organization will hire the right people, and then foster their development in such a way that they are productive, happy, and grow, and will compensate them sufficiently. If any of those things break down, you can run into any number of problems, and they won't necessarily take the form that seems obvious at first.
I've seen organizations take very competent people and ruin their morale and shunt them into projects that were really detrimental to them getting out, in ways that aren't obvious at the time. Or weird organizational dynamics cause changes over time that make someone look bad in ways that aren't their own fault.
There's just weird things that happen that don't simplify to simple models of "talent that is completely independent of environment and perfectly visible."