Cal, Chris and Derick changing jobs

There seems to be a strange mood going on among a few of the top PHP activists and core developers. Chris Shiflett changed job recently (about two months ago), and today Cal Evans declared he would be leaving ibuildings, almost at the same time Derick Rethans stated he would be leaving eZ Systems. The latter two indicated they would be looking for positions that really make them enjoy their professional activities. I believe Chris already found a new position (didn't check that). For the companies they are leaving, this must be a major concern (even counting on a few months to prepare for the cut), as they represent hugely recognized PHP developers in the face of the community. This kind of reminds me that one of my personal objectives for the future releases of our solution is to improve the management of talent as a way to both retain key people by planning their needs of change and also make sure that, if people leave, they also leave behind motivated and capable people that will be able to provide continuity of their work.