Studies also show a correlation (and possibly causation) between FPTP countries and income inequality. Whatever "benefits" FPTP may have, they pale in comparison to all the disadvantages.
Perhaps, but Australia uses Instant-Runoff Voting [1], and we are also following the toxic partisan Us vs Them situation too.
I suspect there's more than one factor at play here.
The PM is elected by the parliament, and often disposed of when they're seen as not doing the job. More turmoil, but avoids a lame duck at the top.
There have been a lot of eerie similarities in Australian politics in terms of partisanship.
Turnbull was ousted from his first turn at Liberal Party leadership precisely because he was seen as 'cooperating' with the Labor government at the time, when he was willing to negotiate and compromise on certain positions.