No one else has the scale to even begin negotiating with the Pfizers of the world. Try to buy something from them directly, and the price would be "Fuck you".

Cost plus pharmacies do still exist. The problem is, some drugs really are just way more expensive, so if you already have "free" (or heavily discounted) insurance from your workplace, it's a bit of a waste not to use it, especially since expensive drugs do also contribute to your deductible.

Also, wholesalers also negotiate with PBMs, so the cost plus pharmacies might not be able to get the drugs at the same rate PBM-friendly pharmacies do.

Go around how? The point is it’s a consolidated monopoly. The same people own every step in the chain. They use this particular step to extract monopoly profits.