The Dems have had an aversion to wielding power when they've had it. If power is given and things still aren't being changed for the better, at what point do you give up on centrism and use the primary to vote in someone who is actually offering to try to change things for the better? With the blase attitude that has been shown by the establishment Dems for the struggles of the working class, do you really believe simply winning is more important than having integrity and conviction?
Why do you believe centrism is the best way to get elected? Do you think centrism is a better tactic than populism?
The way I look at it, centrism has been framed by the media as the winning ticket, but I'm not convinced. We're told that pushing rightwards is what is going to appeal to the most people, but I don't believe that most people actually want that for this country. I do believe the Dem establishment and the media have a vested interest in making people believe that it's true, and they've become very good at controlling the narrative to enforce the idea. To me it seems more like people give up on what they believe in out of fear of asking for 'too much' and risking Republicans taking power, but the line of what is 'too much' was dictated by the media and establishment.
The vibe I get from centrists is that they look down on progressives as dumb or naive for not knowing you're supposed to abandon your hopes of improving society or else, like they were told they needed to do. That being 'moderate' won't ever rock the boat, and therefor won't ever topple the system. I don't subscribe to that narrative and I find the idea that we need to appeal to corporate interests and push things rightward in order to win completely manufactured. Being moderate in the face of extremism is just allowing the boat to rock to one side without trying to shift it back to the other. If/when the system topples, it will be the fault of moderates for refusing to push back.