Loblaw, Sobeys, Metro and Costco sell about 67 cents of every dollar Canadians spend on groceries, by a USDA estimate. The four biggest US food retailers sell about 35 cents.
Be glad you’re not in New Zealand where “Competition is dominated by two major retailers” according to the New Zealand Commerce Commission Market study into the grocery sector Summary of Findings published March 2022.
This is simply the result of Canadian cities with overly anti-small business policies. The fact that you can’t just run a business anywhere, or that you require to have a license from the municipal/city, or even have a permit for a sign out on the street, have a permit for x style of signage, etc. all for the sake of the look-and-feel of a city… is anti-business. It puts barriers in front of lower budget mom/pop stores.
Go out of North America, and you’ll see that when overbearing policies are removed, small businesses thrive, cost of goods go down , and more variety are available to the consumer.
This extends beyond just the grocery market.
Those are all reasonable and necessary restrictions though, not sure why you think they’re burdensome. Things like accessibility, traffic, public safety, etc are part of operating a business.