They have to keep them high to capture maximum reimbursement. If the U&C is below reimbursement max, the PBM only pays the lowest price.
Discount cards were never a huge problem before because they were just the negotiated rate of one insurance company. So there were places where profit could be made as the reimbursement of some drugs was still pretty good and enough to outweigh the prices that were really bad to the point of losing money. With GoodRx, they do a metasearch of a several PBMs and they only give the end user the prices that either lose money or give you like 8 cents of profit. And the pharmacy has to take the card because they have contracts with all of these PBMs that require them to honor the cards. The PBMs don't really give a damn because they see it as free side hustle money. The pharmacy is left holding a bag of ****.
It really is incredibly unfair, TBH. I mean, sure, to hell with our corporate overlords, but it really is unfair. I couldn't imagine being an independent pharmacy and having to deal with this.