I think Bruschi is completely correct - the team has changed immensely, and it's the end of an era.
We won 3 SBs from 2001-2004, and 0 from 2005-2008 (albeit with one near miss). Much as I admire them, Harrison, Vrabel, Bruschi, Seau and Colvin aren't going to get us any more rings.
I think we are at a watershed. Hopefully, when we look back, we will see the 2005-2008 Patriots as a transitional state between the 2001-2004 team and the 2009-2013 team (which I hope to see win at least 2 SBs). Their experience has taken us as far as it can, and their abilities are only declining more and more. We need to move forward, and I think that BB has finally reached the point where he will be ruthless about it.