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It might seem like that if you live in an area with a growing population but you have to remember that big cities with high population densities have historically got by just fine without big box stores. They do it by mixing retail and residential. You don't have a single mom and pop trying to serve everyone in a few square miles, you have a mom and pop on every corner. Open air markets can serve large populations. Delivery is much more common. Even in small U.S. towns if you're old enough you might remember that dairy products were often delivered vs bought in a store. I've had older relatives that used to be "Milk Men".

Big box retail is more connected to the rise of automobile than any rise in population.

Back on topic: Many of the places I frequent by bike have racks but there are places that don't. It's rare that I have much difficulty finding something to lock my bike to but there are times when I really have to look. Since I live in a city there are lots of stores that don't have parking lots. The places that do have lots seem less likely to have bike racks than those that don't. That's not universally true though and it could be more my perception than reality.

I also live pretty close to some popular bike routes so for that reason shops in my area tend to have racks.

The nearest grocery store does have a rack but it's an old fashioned "grid" type. It works. The closest Walmart would be an unpleasant trip by bike anyway. I have no idea if it has a rack. There are Targets that are much closer and they have bike racks.