Did you read the article? It says that "more than half of that waste comes from just five countries in East and Southeast Asia — China, Indonesia, the Philippines, Thailand and Vietnam". All the companies you listed are irrelevant there.
These countries import waste from many other countries, including the US.
They should start thinking about producing enough waste for themselves if they're unable to get by without imports, this creates a huge dependency on the US and most developed countries are completely self-sufficient when it comes to waste production.
Well.. Walmart is a large chain of supermarkets in China, and Costco operate there too, so they're not entirely irrelevant (http://www.wal-martchina.com/english/walmart/index.htm). Fortunately China has like many countries moved to forcing shops to charge for plastic bags so plastic bag waste has gotten a lot less bad in China at least.