I could name a hundred niche sellers too, but the allure of Walmart and Amazon is that they sell basically everything. I can buy a Macbook and Gatorade plus some brand name AA batteries for my RC car that I bought all in the same shopping trip.

IKEA has good products but they don't come close to general merchandise stores like Amazon or Walmart.

What about Costco?

Costco is the opposite of Walmart; they're more like Trader Joe's. They sell hardly anything. The idea of Costco is "if you find it here, it's a decent product", not "if you want it, you can find it here".

Target?