It is much easier to think that nothing has changed if your political memory goes back only as far as the Bill Clinton admin. Older liberals remember that Clinton represented a huge pushback against Reaganism. We remember how overwhelming and depressing Reaganism was. We may feel that Bill Clinton's "centrism" was truly the best we could have hoped for in the 1990s.
We also see how Obama marks a giant step beyond Bill Clintonism (and a rebuke to GWBush), and are therefore more conscious that the long arc of American political history is in fact bending, however fitfully, toward justice. Young liberals see a Clinton as a step back from Obama. Older liberals see the second Clinton (Hillary) as potentially a step forward from Obama because we remember her as a liberal beacon within the Clinton administration.
It is easy for older liberals to believe that while Bill Clinton was a necessary transitional figure, Hillary Clinton has the potential to be the president who secures Obama's achievements and builds substantially on them to lay the foundation for a far more just future.
I remember thinking clearly after Republicans secured congressional majorities during Obama's term that they would overreach by the end of Obama's presidency and inspire a reaction that would elect a liberal Democrat in 2016. To call Trump Republican overreach is a severe understatement.
So here we are. If we don't blow it, all of the elements are in place for a landslide that elects a liberal Democrat as President with Congressional majorities to support her. It could be one of the most progressive eras in American history. The Bernsters cynicism is understandable, but, hopefully, just wrong.