Then there are a bunch who make it to the national level and suddenly think that the prevailing conventional "wisdom" is the way to go, forgetting the guy(s) who "brung 'em." The press smear of Dean in 2004 still reverberates with those of little backbone, who find that it's easier and more comfortable to befriend the corporate PTB. Plus there may have been a lesson intended by Dean's treatment - and it worked, for the most part.
There are some who are the Real Deal at the level of governors. The Governor in my US state of residence, Maryland, Martin O'Malley, is one of these and Gov Brian Schweitzer in my birth state of Montana is too. I also believe that Elizabeth Warren is and will continue to be, whatever the outcome of the Mass election. You may also know some among your own state and local legislators.
But we do need to keep the focus firmly on the local and state levels - the DNC under the usual management just ramps up every four years and could care less. Under Dean, the DNC was rebuilding ALL the state networks that had been neglected for far too long. That is what helped Dems win in 2006 and REALLY helped them in 2008. Dean was very badly treated after 2008, IMO, because Rahm and the "conventional wisdom" guys attributed the wins wholly to enthusiasm for Prez Obama. Yes, Obama's popularity as a candidate helped - a lot - but it wouldn't have worked half as well or as smoothly without Dean's DNC infrastructure and networks everywhere, not just in "key" states, i.e., the "Rahm approach."
But Dean still works very hard through DFA to get liberal candidates elected at all levels. And he will continue to do so. Perhaps someday Dems will finally acknowledge this as they should. But I won't hold my breath.