To be fair, "progressive" as we use it today is fairly new as a political entity. Candidates lioke Mondale(perhaps) could have been described as having progressive ideas, but they weren't in some organized movement of faction.
The Congressional Progressive Caucus was founded in 1991, but they had very few members and seemed more about being pissed at the Democrats running to the right than having real progressive ideas. Although, they did put out an actual plan to fight Gingrich and the Republicans in Congress.
Even to this day, some of the folks in the CPC would probably fit better in the Problem Solvers, but I digress.
Progressivism as an organized movement started taking off towards the end of the Bush adminsitration. After Obama was perceived to come up short in some important areas, Bernie Sanders was able to put progressivism in the spotlight and make it a real force in the Democratic Party. It was so effective, that after Progressives started winning and unseating establishment Democrats at every level, establishment Dems felt the need to shank them and coopt their language to try and win.
So, if the Progressives can take their wins in stride, avoid the type of infighting that can take down up coming movements, and the establishment Dems stop preferring to lose to right-wingers, we may see more progressive senators and governors over the next 10 years.
Not holding my breath over the White House, though.