Well, yeah, but the people working there are not Sony's property, and it's pretty much the thing that matters.
So I guess having a good relationship with them and making them happy could be one of Sony's priorities.
It most likely was not what he meant, but saying "ND is Sony, this doesn't matter" may not be exactly true.
Except Sony has been replacing key staff at ND for nearly as long as they've owned them, without missing a beat.
Rubin and Gavin were only around for 4 years after the purchase. They left and Sony replaced them with Amy Hennig who wrote The Last of Us. She's still with them but they had Druckman work with her on Uncharted before tapping him for The Last of Us.
Same with Sony Santa Monica. Jaffe led the first God of War, then left so they had Barlog lead the second game where he topped it's predecessor. Then he left, Stig Asmussen took over and delivered an exceptional God of War III. He's now making his own IP and they had Toddy Papy direct GoW: Ascension instead. Hell, even with Ready at Dawn handling the PSP games they had Ru Weerasuriya direct the first game and Dana Jan direct the second (Werasuriya did help write both games, as did Barlog).
New director every God of War game, never missed a beat.
Sony's first party studio managers have an eye for talent and it's not exactly easy to poach someone like an Allan Becker type when Sony promotes them up the executive ladder aggressively and no other video game industry entity really rivals the scope of Sony's corporate hierarchy.
Worldwide Studios bleeds talent all the time but they replace with similar talent just as quickly. In turn they offer anyone who works for them exceptional levels of creative freedom, funding, and technical support. That is how you get the best results out of your creative staff, and something Sony Computer Entertainment at least has made part of it's corporate culture.