During the campaign itself: almost never mentioning issues in her ads so liberals/Democrats had nothing in particular to vote for even though her party is generally supposed to be on the more popular side of every major issue, focusing on what an unpolitical personality her opponent was when his unpolitical personality was what had gotten him that far in the first place, whining about how her opponent who focused much more on issues is being too personal, perpetually badmouthing & thus alienating voters with exactly the same kind of SJW crap that had turned "SJW" into a backlash term in the first place that she's still saying in that "taking responsibility" article, participating in the transparent antidemocratic rigging of the "Democrats
'" system against a Democrat whom voters were far more in favor of, and taking battleground states for granted & doing nothing there.
In the background before the campaign, creating people's general impressions of who she is before she even started: a history of voting largely as a Republican (particularly on wars and trade deals) including openly switching sides after taking corporate money (such as
opposing universal health care after taking pharmaceutical industry money), siding with a misogynistic sexual assaulter/harasser against his victims (the perfectly targeted setup for eventually not being taken seriously against another guy just like him when she suddenly starts claiming to be on the women's side instead this time), and a list of years of assorted scandals, lies, & general political sliminess & self-centered-ness including general disdain/hostility for the American people occasionally oozing from her words.
She should have bowed out and let Sanders get the nomination. He would also have lost
You're saying, quite mathematically literally, that the country's most popular politician would have lost against its most unpopular Presidential candidate ever. Polls consistently showed, and still do, that he would have won by several times her popular-vote margin, enough to overwhelm the Electoral College problem even if he had made the same bad decision about not campaigning in battleground states.
And it's not hard to see why. He talks about issues, not personalities (including shifting to the former even when a reporter/interviewer tries to pull him over to the latter), and the issues he talks about have most Americans on his side. He gets standing ovations from audiences full of
Trump voters when he talks about ending free trade deals that export jobs. Medicare-For-All, universal health care in general in any other form, free college, a livable minimum wage, and stopping military interventionism all have support from such large majorities of the general American public that most or all of them have a majority even from
Republican voters.
The idea that Democrats need to avoid populism and be corporate-political machine Republicans by another name in order to win is a myth, a lie told by corporate Democrats to maintain their power within the party while continuing to oversee the party's slide out of power and out of relevance. Those moderate, middle-of-the-road voters they say they're after just don't, in reality, vote for Republican Lite against the real thing, but they do vote for an alternative that's an actual authentic alternative, when they can find one.