2016 Postmortem

Though she did end up with about the same number of votes as Obama received 4 years ago.

First of all, Obama was replacing Bush. Obama is younger and had less political history to critique (Clinton was victimized by decades' worth of hate--someone else with the exact same message and strategy would have carried those battleground states, even if that person also faced unprecedented FBI interference).

Obama preceded the 2013 Shelby County v. Holder decision, which enabled massive voter suppression.

Throughout US history, there's been a white backlash against racial progress (including the election of Obama and his executive action that produced DACA)--that backlash has built up over the last 8 years and was exploited by an overtly bigoted candidate who was endorsed by the KKK and sucked all of the media air(waves) out of the room. Add that to the overt misogyny in a race against the first major party female candidate in history.

And, yes, Obama did more outreach to the rural areas of purple states like Iowa.

None of which changes the fact that the "working class whites/economic messaging" narrative collapses under scrutiny.