This is one way of showing an info. A negative one. A typical media style.
The current market price of a branded medicine is based on its development cost and history and not on cost of present component purchasing.
Ex: As per Sonofi pharma, Plavix development cost was a whopping 4.5 Billion dollar covering 15 years. This cost has to be recovered within ten years, since after ten years, FDA releases generic permission to any manufacturer. Its quite complex.
Its not about costco or walmart, its about development. The medicine list given by you are now over ten years old and available as generic. smaller unknown manufacturers are now enjoying cheap production and profits with no binding to give desired results. No one even knows their country of manufacturing and in third world countries, there is big money and fraud in generic business.
A toyota car production cost may be just five thousand dollars, but they can't sell it for six thou. The design and development costs of any product are always exorbitant and manufacturing is done for profits, job creation and progress.