It's not like they didn't have information about this in 2008 when primary voters ended up picking Obama over Hillary in the first place.
[N]ew information shows that Clinton had a much bigger problem with voters who had supported President Barack Obama in 2012 but backed Trump four years later. ... Turning out the base is not good enough, the data suggest.
But Hillary didn't turn out the base in 2016 anymore than she did in 2008. Every single story from the Democrats ignores that Democrats revolted against Hillary in 2016 just as they did in 2008. Just as they did in 1993.
Just look at the top vote-getters by state since 2004.
Trump 2016 was the top-vote-getter in AL, AZ, AR, FL, GA, IN, KY, LA, MO, MT, NC, ND, SC, TN, TX, WV, and WY for a total of 26.4 million votes. Seventeen states, two of them swing states.
But eight years ago Obama 2008 is still today the top-vote-getter in CT, DE, HI, IL, IA, ME, MI, MN, NH, NJ, NM, NY, OH, OR, PA, RI, VT and WI for a total of 28 million votes. Eighteen states.
Hillary 2016 was the top-vote-getter only in CA, CO, DC, MD, MA, NV and VA for a total of 16.6 million votes, over half of which were in California. Six states and DC.
Obama 2012 was top-vote-getter in WA, Romney 2012 in ID and UT, McCain 2008 in AL, MS and OK, and Bush 2004 in KS, NE and SD.
That's all fifty states plus DC.
Trump is somewhat weak with his base in 8 states going back to 2004, but Hillary is far weaker with hers.
That's the story which has been ignored over and over again since election night. Hillary underperformed Obama 2012 in 34 states, but Obama 2008 in 39.
They weren't with her. Ever.