People often write me to tell me that I am full of shit. Experienced designers and savvy project managers are often able to articulate usability principles very well, and they get angry when it seems like I am divorcing usability from development. They understand user-focused design, and they work hard to ensure success for users. It makes them successful, so of course the good ones do it. In many work environments, the central problem with usability is that it is ignored.
People understand what the goals are and they can often act using usability testing methods.
Thus, experienced designers and project managers feel they don't need extra usability help. Interestingly, the best folks really don't need much help. Despite recent things I have been told, doing usability day to day does not require incredible amounts of brainpower. Before you get upset, let me explain. Usability in the trenches, when you really get down to it, requires having people around who have great attention, are compassionate about users, and can listen.