Given the system we have, this is a non-issue.

In a perfect world we wouldn't need capitalism at all, but we don't live in a perfect world. We will never have a perfect world, humans are not perfect. We're greedy little fuckers.

A 4.2% Profit is very low. Extremely low. That profit level is actually so low that it's almost losing money for investors once you account for inflation. Any lower and there wouldn't be any investors, and we'd see grocery store closures and price increases until it went back up again to attract investment.

Now don't get me wrong, I'm very much for socializing certain industries. Healthcare, Electricity, Internet/Communications, Water, Sewer, Roads, should all be run by the government in my opinion. They each have particular problems where Capitalism has massive market failures. Healthcare is too necessary and usually too urgent to be able to "shop around" for the best deal. Electricity and Internet have natural monopolies on transmission due to infrastructure building requirements.

This just doesn't apply to grocery stores. There's some fierce competition among the major players, minor players exist, and there isn't an obvious market failure like regulatory capture or a monopoly leading to ridiculous profit margins or an inability for new entrants to join the market.

https://en.wikipedia.org/wiki/List_of_supermarket_chains_in_Canada

In my mid-sized city, there all three major players present of course (Pattison, Loblaw, Empire), then we've got walmart, costco, whole foods, h-mart, and I know of at least a dozen smaller grocers and full time farm markets that aren't even chains. There's even a co-op grocery store owned by members.

I don't mean to downplay the situation, but it's quite clear when you look at the numbers that grocery stores are NOT the root of the issue with food price increases.

If you really want grocery stores to drop the prices more, do you know what would be even more useful than taking their 4.2% profit? Take the land from their landlords, and lease it to them for $1. Grocery stores typically are paying 4-8% of their total revenue in land prices.

The highest costs of grocery stores (in descending order) are Inventory, Labour, and Rent.

Now imagine if, instead of just dropping their rent prices, you actually dropped the land/housing costs for EVERYONE. That reduces how much the famer needs to spend, that reduces how much the processing plant spends, that reduces the amount the manufacturer spends, that reduces the amount the warehousers spend, and it reduces the amount the grocery stores spend.

It gets worse though when you realize that housing prices are also why labour prices are so high. If your rent/mortgage was half, you wouldn't need to be paid as much money to have the same standard of living, it wouldn't reduce your costs by half, there are non-rent costs in your budget, but say you earn the median income of $80,0000, and you're spending $3000 a month on rent for your family, if your rent dropped to $1500, you could earn $62,000 and have the same life. That's reducing labour costs by 22%.

Then take that and apply it to the entire chain as well. Reduced labour for the famer, processor, manufacturer, warehouse, grocery store.

This is the big thing people are failing to understand. Land owners are taking a huge cut of everyone's money right now. This is where the money flows to in the economy. I'm not talking about corporate land owners either, I'm talking about every single person who owns real estate from some random big corporate entity all the way down to your parents who bought a house 20 years ago and have seen it's value go up by 4x since then. That value had to come from somewhere, and it's coming straight out of everyone's pockets in the form of higher prices.

It's a hidden tax on everyone that the government controls through policy, but which the government doesn't receive the money for.

The government has the power to end that, but there's very little appetite for it because it's far too removed from public understanding for the public to even know what to ask for to fix it.