> I recall, more hazily, that the previous federal election (so several prime ministers ago)
The most recent federal election was this year. The previous federal election was 2019. There were no changes of prime minister in that time; Scott Morrison was the prime minister going into the 2019 election, and Scott Morrison was the prime minister going into the 2022 election. I realise this takes a bit of getting used to, since the last prime minister to get from one election to another was John Howard.
> a lot of ersatz democracies where only two realistic options are presented to the population to pick from.
Only the US has two realistic options, or else your statement is meaningless. Come up with a countexample.
In the UK and Canada there are three parties who regularly win general seats namely the Tories, Labour and the Lib Dems, or the Tories, the Liberals and the NDP. They both also have Greens who can win certain seats. Moreover they also have various regional parties e.g. Bloc Quebecois or the SNP who compete against the general parties in their regions of interest. In such a system, there might only be two realistic possible governments foreseen by observers, but voters act as if there's more than two realistic options to vote for, and they vote for more than two options, and more than two options get seats.
Various other countries have two-bloc politics where you can give your vote to a left coalition or a right coalition, and to a certain party within that coalition. For instance, in NZ you can vote for Labour or the Greens if you like the left, and you can vote for National or ACT if you like the right (notice how the Greens got a ministry after the last election, even though Labour got a majority in their own right). But in such a situation there's clearly more than two realistic options to vote for, even if there's only two possible governments foreseen.
(Not to mention that you can also get the situation where no precommitments are made, or the precommitmentments are rendered vain by results, and coalitions have to be formed after the election. But I assume this is regarded as the ideal.)
Fundamentally the way people choose to describe a political system depends on the conclusions they intend to draw from it. The UK and Canada are substantially similar, but people want to praise Canada in comparison to its neighbor, and criticise the UK in comparison to its neighbors, so the UK gets called a "two-party system" and Canada gets called a "multi-party democracy". (Both are also sometimes describe as having proportional voting, since minor parties win: but this is false. Neither Canada, nor the UK, nor France have proportional voting.)