https://www.cnn.com/2022/09/20/business/credit-card-fees-vis...
Costco gets away with 0% because they offer exclusivity and because they cover some of the cost of the rewards programs. I guess Walmart et al did the math and figured they would lose too much business.
The average Costco shopper makes over $100K a year, so getting another card just to shop there isn't a problem for most. Can't say the same for Walmart.
While technically true, that statistic is misleading as it requires further qualification, namely that $100k figure only applies to shoppers in Costco's PNW area - not nationwide, and certainly not internationally.
More recent attempts at analysis put the number closer to $125K these days for all their customers worldwide.
Which makes sense, given inflation and the fact that they only build Costcos in more affluent areas and target business owners.