Another week, another ignominious end to what had seemed a grave threat to Australia’s two-party establishment.

Actually, make that multiple threats — between South Australia and Batman, Saturday proved to be a bad night not only for the Greens and Nick Xenophon, but also for Cory Bernardi, whose much-hyped Australian Conservatives couldn’t even match the past achievements of Family First.

This follows underwhelming performances by One Nation in Western Australia and Queensland last year, and a golden duck for the Jacqui Lambie Network in Tasmania a fortnight ago.

With whiplash-inducing speed, media takes about the frailty of the two-party system (including not a few of my own) have made way for prognostications on the failure of its challengers to match expectations (including the one you’re reading right now).

Had the expectations game played out differently, reactions to Saturday’s results could have been very different.

The Greens may have failed in their bid to expand their inner-city domain beyond Adam Bandt’s seat of Melbourne, but they did outperform their previous best primary vote in Batman by 6% (aided, admittedly, by the absence of a Liberal candidate), and achieved their second best two-party result after 2016, when Labor was carrying the considerable dead weight of David Feeney.

Even so, their two-party vote in equivalent booths was around 2.5% weaker than at the Northcote state byelection last November — and it was at this end of the electorate that the damage was done, with the more Labor-friendly northern end recording a slight swing to the Greens that might have got them over the line if the south hadn’t moved sharply the other way.

As such, the most persuasive explanations for the Greens’ defeat relate to their failure to lock in support from their natural inner-city constituency.

Richard Di Natale focused his ire on those elements in the party that undermined Alex Bhathal’s campaign, and while this was no doubt unhelpful, he might also consider the possibility that his efforts to exploit disquiet over Labor’s dividend imputation policy backfired among younger progressive voters.

The other lesson is a rather obvious one for Labor: run a Ged Kearney or an Anthony Albanese in an inner-city seat, rather than a David Feeney, and you’ll have a lot less trouble from the Greens.

In South Australia, Nick Xenophon’s failure to establish a power base in the state’s lower house, or even to sustain his own career in the immediate term, has understandably hogged all the headlines — but it should not be forgotten that the state delivered a record-breaking 29% of the primary vote to minor parties and independents.

However, thanks to the single-member electoral system, the Liberals are almost certainly set up for majority government, even if the fairness of their doing so with less than 38% of the vote is being too little discussed.

Steven Marshall’s incoming government owes its election not to its success in seizing the agenda during the campaign, nor even to the Weatherill government’s electricity and nursing home disasters, but to the rather less exciting contingency of new electoral boundaries.

This was actually the third election in a row at which the Liberals won the two-party vote, and they appear to have done it by a smaller margin than in 2010 and 2014, with Labor gaining a swing of just under 2%.

When the Liberals were left champing at the bit with 51.6% of the two-party vote in 2010, the boundaries commissioners resisted their entreaties to level the playing field by loading the next redistribution in their favour.

Then came an even worse injustice in 2014 — a 53.0% two-party vote for the Liberals, but another term in power for Labor, albeit as a minority government.

As the Liberals cried blue murder, the boundaries commission indulged them with an exercise in noble-cause gerrymandering that effectively flipped four seats from Labor to Liberal.

Had the 2014 election been held under the new boundaries, the Liberals would have won 25 seats out of 47 — which may very well be where they end up this time, after winning at least three of the four aforementioned seats plus a newly minted marginal seat in Adelaide’s outer north.

Nowhere did the Liberals unseat a Labor member without a free kick from the redistribution, and they might yet lose their seat of Adelaide, which Labor had targeted with a promised tram network.

All told, it was a fairly modest win against a government that had well and truly outstayed its welcome – but a win all the same, and one achieved in a historically difficult state.

From the perspective of the Turnbull government, perhaps the most heartening aspect is that the conservatives outperformed the polls and the advance expectations of the pundits — something they have been making a habit of lately, following the New England and Bennelong byelections and Will Hodgman’s decisive victory in Tasmania.