In Québec, (some) of the grocery price tags include a fine print with the $/100g.
They go out of their way to make this the smallest thing possible though.
There’s plenty of other misleading tagging going on too.
And I think it’s only certain items, maybe not all.
It’s a good idea and helpful, but should be more prominent and apply to literally all foods.

And that’s before tax, although not all foods are taxed.