I think this is the point that's really missing; that it isn't just the person and the environment need to match, as though the environment is some immutable th

I think this is the point that's really missing; that it isn't just the person and the environment need to match, as though the environment is some immutable thing. As a manager, you have to notice when your "A" players are falling and change things if necessary. You can change the environment to make more "A" players out of your team. Though, sadly, more often management winds up making "B" players out of "A" players. Or making ex-employees out of them. By the way, there is a counter-argument. The true "A" players are go-getters who bring about organizational change, who seek out challenges in an unchallenging environment, etc. The "B" players aren't demotivated by bad management, a hostile environment, lack of freedom or respect - they're people who are just naturally unmotivated, lazy, etc. I hate that argument, of course. It suggests motivation and productivity is just some innate, immutable trait. And ultimately, it exists to excuse managerial failings.