It was always going to be a matter of when, not if, Coles and Woolworths would fall from the public's good graces.

High grocery prices and even higher profits, an interview that went viral for all the wrong reasons, and countless same-same-but-different inquiries haven't done the supermarket giants any favours with Australian households.

That much was made clear in a survey about trust — both had enjoyed sky-high reputations so carefully fostered during the pandemic in the days when shopping for groceries doubled as social outings.

But what goes up must inevitably come down, and last month Roy Morgan found our distrust now outweighs any goodwill Coles and Woolworths had earned, as the cost-of-living crisis followed by near-constant price gouging allegations explained their rapid demise.

With a near-unanimous verdict in the court of public opinion, it's hardly surprising that a government that's made cost of living relief a centrepiece of its first term in office has zeroed in on the supermarkets.

After all, nothing brings people together quite like the seemingly universal concern of getting ripped off at the check-out.

The devil is in the detail

Back in January, the federal government announced it was getting serious about supermarkets by asking the Australian Competition and Consumer Commission (ACCC) to put the sector under the microscope for 12 months.

Specifically, the competition watchdog was directed to examine supermarket prices and investigate whether the repeated allegations of price gouging actually stacked up.

It's the first time since 2008 that the ACCC has been tasked to look at the supermarkets — a review that helped pave the way for unit pricing on shelf labels — and it's no small project, given how much has changed in 16 years.

But tacked onto the end of the government's press release was a $1.1 million commitment for consumer group Choice to compare prices across the supermarkets and release its findings every three months for three years.

The government pitched it as a way to "provide price transparency" and "empower Australian consumers" about their food and grocery purchases — claims repeated in its May budget.

Now with July around the corner — and the delivery of ex-Labor minister Craig Emerson's review into the (voluntary) grocery code of conduct fast approaching — we've arrived at our first milestone: the inaugural Choice supermarket prices report.

The results were hardly surprising for anyone who's set foot in a supermarket in the past 18 months.

Buying a shopping basket including beef mince, tea bags, tinned tomatoes, carrots and 10 other staples at Aldi was roughly 25 per cent cheaper than it was at Coles and Woolworths, while prices at the big two were practically identical.

The report hadn't even been publicly released before the supermarkets were questioning how Choice had reached their findings.

What were the grocery items? How many home brand products made it into the shopping basket given that Aldi doesn't stock many of the major brands? Why was IGA ignored everywhere except for Tasmania and the Northern Territory?

Privately, the shared supermarket sentiment towards the report was: "Tell us something we don't know."

As one insider wryly remarked, they were compelling findings from a government-commissioned report that effectively cost taxpayers $92,000.

Change doesn't happen overnight

In the same way that a supermarket isn't built in a day, nor will a single report looking at grocery prices make your next shop cheaper.

No-one knows that more than Choice — it's perfectly aware that it can only do so much in the current climate.

The consumer group says the real value will come as it sends more mystery shoppers into more supermarkets around the country to deliver more reports.

Regardless, they've put the supermarkets on notice, whether the sector likes it or not (and whether they agree with the methodology).

It's also precisely what the government is aiming to achieve: the impression that yes, it can in fact do something about supermarket prices right now.

But as the saying goes, doing the same thing over and over expecting a different result is the first sign of madness.

So what does it mean that there seems to be inquiry after inquiry into supermarkets and grocery prices?

Groundhog day

If you put aside the politics of the different inquiries that have come and gone in the past six months, they're largely not telling us anything different.

There have been six inquiries running at the same time on a national level — five of them at the direction of the federal government — and another two by the Queensland and South Australian governments.

The outlier is the union-backed price gouging inquiry chaired by former ACCC boss Allan Fels, which handed down its findings in February.

In it, Professor Fels commented that there hadn't been a "price war" between the supermarkets in years because there was insufficient competition.

The following month, the Greens-led Senate committee investigating supermarket prices delivered its report, which made repeated references to a lack of competition in the sector, and the need for stronger competition policy.

(Both Coles and Woolworths are adamant that there's plenty of competition in the supermarket space.)

The Senate inquiry also recommended the grocery code of conduct be made mandatory, as did Dr Emerson in his interim review of the code a month earlier.

The common denominator with all of these reviews and reports is that the evidence is often coming from the same experts — the only difference is the dates on which they give it.

So far, the ACCC has received more than 21,000 submissions into its supermarket inquiry, and it's in the middle of drafting its interim report to hand to the government by the end of August.

The final version will be signed off on next February, just in time for a federal election campaign that could very well see the tinned tomato can kicked under the shelf.

Whether it will make a difference is another thing entirely.

After all, the ACCC's grocery inquiry in 2008 found there was healthy competition in our supermarket sector — back when Aldi had under 200 stores, Costco hadn't turned the sod for its first warehouse, and Amazon Australia was nine years away from launch.

Having too much evidence is never a bad thing. But if sunshine is the best disinfectant, the repetitive flickering of the fluorescent lights won't cut it.