PBMs hold an incredible amount of power. The Acquired podcast did a marvelous breakdown of the American pharmaceutical industry while covering Novo Nordisk (https://www.acquired.fm/episodes/novo-nordisk-ozempic). If you have three hours to spare, I highly recommend giving it a listen.
Another great interview comes from Mark Cuban, who is serious about disrupting PBMs with his Cost Plus Drug Company (https://www.drugchannels.net/2024/03/mark-cuban-five-ways-th...).