What happened then to Biden is what's happening to him now. The more the voters get a look at the actual Joe Biden, and not just his resume, the less they like him. We can focus all we want on policy statements, voting records, etc. But in the end, the voters always choose the most persuasive candidate.

But anyone who really knew Biden and his personal political history also knew that we've been in this place before with him. On paper, Biden has always seemed more formidable than he ends up being on primary election day. His short-lived previous presidential campaigns in 1988 and 2008 both ended with no primary victories or even top-two finishes.

The answer is Biden's cachet in this election cycle has always been what people assumed his strengths would be. A long-time senator and former vice president from a blue-collar state like Delaware was presumably a natural threat to President Donald Trump in the general election. All the polls said so for what seemed like more than a year, didn't they?

But the more important questions to answer are: What happened? Why did Biden fall out of favor so quickly?

Yes, there are a couple of examples of candidates who failed in Iowa and New Hampshire who went to win their party's presidential nomination. But none failed as spectacularly as Biden has.

After a humiliating fifth-place finish in the New Hampshire primary and an apparent fourth-place finish in Iowa, former Vice President Joe Biden's presidential hopes are finished. You can expect him to maybe stay in the race for another three weeks or so until the Super Tuesday primaries are over, but that's about it.

Biden, other than his many U.S. Senate election wins in his tiny state of Delaware, has never been a very persuasive candidate for a wider selection of Democrats. As long as his candidacy most closely mirrored that of a "generic Democratic challenger" to Trump, he was going to lead the field in the polls. But once the voters got a closer look at the real Biden with his actual campaign persona, they quickly changed their minds just as they always have.

All of us got to see an example of how Biden starts strong, but finishes weakly, just a few days ago in New Hampshire. At a town hall campaign event, a Democratic Party voter asked told Biden she had a tough question for him. Biden played it brilliantly at first, comically taking off his jacket as if he physically needed to prepare for the tougher question.

Then the woman proceeded to ask Biden if he could recover from his weak finish in Iowa. Biden began by trying to explain that Iowa's caucus system is different and he quickly asked the woman if she had ever been to a caucus. When the woman answered that she had, Biden fell off the proverbial cliff, calling her a "lying dog faced pony soldier." It was bizarre and insulting, (the woman told reporters she felt humiliated by the comment), despite the Biden campaign's insistence that it was just a good-natured jibe.

The predictable effects of the impeachment process didn't help Biden, either. Shining a repeated light on the fact that Biden's son Hunter did receive a lucrative foreign job he wasn't apparently qualified for certainly didn't help Biden's brand. With the impeachment trial wrapping up the same week as the Iowa caucuses and less than 10 days before New Hampshire wasn't ideal for team Biden.

But Democrats will be foolish to put too much stock in the allegations against the Biden family as the reason for the former vice president's latest campaign demise. At best, the allegations of corruption are more like one of those fake excuses people use for not choosing a candidate when the real reason is they just don't personally connect with him or her.

Biden's lack of persuasive abilities outside of Delaware is what's always doomed his White House aspirations. A few more years of experience and opposing Trump were never going to change that. More than three decades of history was staring the Democrats pushing Biden's campaign all along, and they should have seen this coming.

Now, the big question is who will reel in those Biden defectors in the future primary races. So far, it appears the lion's share of Biden's voters have swung to former South Bend Mayor Pete Buttigieg with a decent share also going to Sen. Amy Klobuchar of Minnesota. That development could be enough to derail the path to the nomination for Sen. Bernie Sanders. But Sanders seems likely to pick up all or most of the voters still supporting Sen. Elizabeth Warren's flagging campaign.

Some Biden supporters may also switch to Mike Bloomberg, but Bloomberg will now have to work harder to snatch them away from Buttigieg and Klobuchar. In some ways, Bloomberg's challenges have just become harder because he's squaring off against two Democrats claiming the "moderate candidate" mantle instead of just one.

All of the remaining Democrats still have to pass that all-important persuasion test. Biden's "great pretender" campaign is all but officially over, but his inevitable exit from the race will only make the harsh spotlight shine brighter on the remaining field. It's not clear yet whether the new contenders are going to be competitive for the rest of the primaries, or just the temporary beneficiaries of Biden's fall.

Jake Novak is a political and economic analyst at Jake Novak News and former CNBC TV producer. You can follow him on Twitter @jakejakeny.