It's all Shane Warne's fault. Or Warne's and Glenn McGrath's together. It's Adam Gilchrist's fault. Jacques Kallis is also to blame and so is Andrew Flintoff.
Severally and together, these superstars propagated the idea that a cricketer can be several players in one, so giving his team an extra man or two.
The orthodox description is all-rounder. About Kallis and Flintoff, this was obvious enough; they were titans with bat and ball. But Gilchrist also was an all-rounder, doing the work behind the stumps of a pretty good wicketkeeper and making the runs of a great batsman.
Technically, Warne and McGrath were not all-rounders. But each was both a strike bowler and a stock bowler in one, each having the impact of two. That's about as all-round as you can get (Garry Sobers was three-in-one, but he was Sobers).
But they all retired. Succeeding them, Shane Watson was by comparison a workaday all-rounder, solid but only rarely game-breaking, who at length went the way of all all-rounders: when he became sparing and reluctant as a bowler, his batting was not enough to save him.
Which brings us usefully to Mitch Marsh, who replaced Watson after the first Test of last year's Ashes series and has been there for all except one match since. It used to be that if you had an all-rounder who was good enough, great, but if not, you played specialists. In the Lehmann era, Watson and Marsh have been picked as all-rounders strategically, to give cover to the seam attack, meantime hoping for a smattering of runs.
The only time this policy was varied was when Shaun Marsh replaced brother Mitch for the fourth Ashes Test last year, and Australia played a top six of dedicated batsmen. Ha! Infamously, Australia were bowled out for 60. Less remembered is that Australia's three-man seam attack also floundered as England replied with 391. Mitch Johnson, in the role of a quasi stock bowler, took 1-102, the sort of day of lackey work that would send him into retirement before the year was out. In an odd way, Lehmann was borne out. Without any one-and-a-half bowlers, Australia needed another half bowler.
Fourteen Tests later, though, it has to be said that it is not working. Marsh is pottering along at 24 with the bat and 36 with the ball and Australia are sliding down the rankings. The time has come to go another way. If Australia cannot sharpen up the bowling by deploying an all-rounder in the top six, then it must stiffen the batting by extracting runs from the lower order.
If it is doubtful wisdom to play a batsman because he can bowl, it would be folly to play a bowler merely because he can bat, so inevitably, this responsibility devolves onto the wicketkeeper.
For a generation or two, run-making has been a wicketkeeping KPI. Good enough with the gloves, X factor with the bat; that was the job description well before Gilchrist, but having its acme in him.
Peter Nevill hasn't done much wrong, but in Australia's position now, mere blamelessness is not enough. A more forceful mark is needed. At the WACA on Monday, Nevill was a picture of admirable stoicism, but in the cause of stopping up the dyke. The hole remained. Matthew Wade averages 40 in first-class cricket and 35 in Test cricket, with two centuries, and is still just 28, the age at which Gilchrist made his debut. His claims are still valid.
I understand the illogic: trying to fix an inadequacy by meddling with an adequacy. In an ideal world, or another team sport, these contemplations would be more fluid. Numbers 6 and 7 in the order would be part of a continuum, between them yielding enough runs, wickets, overs, catches and stumpings to the general well-being. But cricket is first of all its parts and only then their sum, give or take. Australia's parts are not working, and not adding up.
Australia are sliding down the rankings. The time has come to go another way.
Who would have thought that Watson would be so missed?