As I said above, I think she sees where the demographics are going and will likely break permanently with the party’s Boomer establishment when it comes to running on the kind of triangulating neoliberal-lite policies that worked for a time back at “the end of history.” It’s one of the reasons I like her and see her as viable presidential candidate in 2020.
My sense is that it’s a reflection of younger people’s anxieties about the DNC establishment’s complacency and arrogance and reluctance to adapt during the 2016 primary and general election. No-one, especially not Millenial Dems, wants to see a repeat of that, so it’s kind of a warning signal: the stakes are too high to continue supporting the likes of Feinstein and her Third Way policies.