The number of 24/7 options has been declining in Thunder Bay, especially in the past couple months, likely due to the minimum wage increase and low sales to support it. Currently we've got a couple 24/7 Mac's/Circle Ks (which ones are 24/7 varies from month to month which is kind of annoying), one 24/7 Shoppers Drug Mart (used to have 3, but two stopped staying open at night), two 24/7 Metro grocery stores, about half of the Tims Horton (used to be more of them, and their overnight selections are bare-bones) and a couple Robin's Donuts (used to be all of them), a couple of the Shell gas stations had a Subway restaurant affiliated with them which would operate 24/7 but those are gone. Mr. Sub recently ended its 24/7 service. McDonald's and A&W have 24/7 drive through service, 3 and 2 locations respectively. A couple gas stations are 24/7. The hospital and police station are 24/7.
I think Pizza Hut or some other pizza delivery company here had 24/7 delivery until about 10 years ago. We have a 24/7 bakery/pizzeria downtown that's quite popular but they don't deliver.
I got really annoyed when I was in Winnipeg in 2012 because not only does that city somehow have fewer 24/7 options than Thunder Bay, but they also keep shit closed until noon on Sundays.
I think the main reason we have so many 24/7 options (and the reason they were so common in the part of town I grew up, near the highway) is because we're basically the only place for travellers to stop in the region, so people are more likely to stop in to businesses here between midnight and 6am than in other places.
A few stores have tried 24/7. Not Home Depot, but Walmart and Superstore both experimented with it on year for about 2 months leading up to Christmas (last year, neither stayed open after 12am leading up to Christmas; probably due to low sales in previous years). The Chinese restaurant across the street from me used to stay open until 2 or 3 in the morning but lately they've barely opened at all.