With these “dad joke” sensibilities, Xenophon’s manner on the hustings is a study in distracted freneticism, warmth and aself-effacing friendliness, as he doles out reassurances under the banner of not being like the major party politicians.

It’s an unorthodoxy that had elevated the former independent senator to almost pop-star popularity in South Australia. It helped him secure multiple state upper-house quotas and delivered a team of four to Canberra following the 2016 federal election.

His bombshell decision to vacate the Senate late last year to lead a massive electoral attack on the major party “duopoly” in the March 17 state election caught many off-guard. The major parties were horrified. Early polls showed given the choice between a trouble-plagued 16-year-old Labor administration and a somewhat lacklustre Liberal alternative, South Australians were more than open to Xenophon’s third way.

But it didn’t last. On Saturday night his dream of leading half a dozen new SA Best MPs in the state’s 47-member House of Assembly collapsed, with not a single candidate elected. Xenophon, who did not even finish second in the seat he was contesting, had been thrashed.

As of Sunday afternoon, SA Best secured just 13.7 per cent of the primary vote in South Australia's lower house, compared to Labor's 33.9 per cent and the Liberal Party's 37.4. In the upper house, the result was a slightly improved 18.9 per cent.

He has since ruled out a return to the federal sphere, and is unemployed. His next move is unknown, apparently even to him. "I take responsibility," he told Fairfax Media on Sunday. "Now it's time for others to shine."

Former Labor campaign director and ex-Keating government minister Chris Schacht lives in the electorate Xenophon contested and watched with fascination as the SA Best balloon rose and fell over the last three months.

Asked why it ended so badly, he offered two words: "Peparation, and expectations".

"Not enough of the first, far too much of the second," Schact said.

"Once the campaign was on, he came under incessant attack from the major parties who rightly asked 'what are you policies?'

"Every time he was in a debate, there were just these great gaps … in large areas he simply didn’t have detailed answers."

Schacht said Xenophon's push came too late and with inadequate preparation, meaning his candidates were not allowed to speak on policy because they were untried and too often there was none anyway. It put an enormous burden on Xenophon, who also lacked the major party machinery to compete.

“He was being included in the leaders’ debates and numerous forums but because he had insufficient policy and no shadow ministers, was required to do it all himself,” Schacht said.

“He should have spent a year at least organising things and quietly putting together a 100-page policy document, but instead he was reduced to promising inquiries in key policy areas like health.”

Xenophon agrees he tried to do it all too quickly, but notes there had been a strong mood for change.

There’s no doubt he had too much ground to make up organisationally, financially, and philosophically, and too little time. Yet perversely, he may have also been a victim of his own early success.

Strategists on all sides suggest the single worst thing that happened to Xenophon was a Newspoll just before Christmas that put support for SA Best at 32 per cent compared the Liberals on 29 and Labor on 27.

"From that moment on, he was considered by voters to be a serious contender,” said one Liberal strategist. "And that comes with obligations, you have to have all the answers, he didn’t, he got found out."