The democratic establishment downplays it, but people are pretty starved for non-establishment, non-corporate, left candidates. It’s quite easy to win a general if you appear convincingly progressive since, policy-wise, that’s what the majority of Americans want.
Fetterman checked those boxes pretty convincingly, especially when stood alongside some like Mehmet Oz who was the most inauthentic opponent Fetterman could’ve run against.
It’s a good object lesson for study, and progressives should use it to identify weaknesses in their strategy for identifying and lifting up genuine progressive candidates.