This I think you have backward. They didn’t sell their values, they realized that controlling corporations was the ticket to power. The formula is simple. You increase your own power to harm corporations. You then use that power as both carrot and stick; you can punish or disadvantage a corporation that misbehaves of doesn’t toe the line, and advantage and protect ones that do. Once you’ve established you have that power the corporations will pay to play ball.
The tech industry learned this with the Microsoft cases. The automotive companies learned it decades ago, as did the pharmaceuticals companies. Obama made an open invitation to the coal cronies during his campaign; and the media on every side missed it entirely.
The American left has been about control and power for several decades now. That is the extent of the common values the American left has. Controlling corporations is power, so what is commonly labeled (I believe incorrectly) as selling out by politicians is really learning some of the lessons of fascism — control of the people through control of the corporation.