Couldn't read the article, but isn't broadcam a fabless company? What's the arrangement? Did OpenAI license and modify some existing Broadcom chip?
Broadcom does custom silicon design as well [0]. If a company like Google or Microsoft wants their own custom ASICs to train models on, they tend to work with Broadcom to design 'em.
This is something Nvidia has been historically bad at. It's basically Broadcom and Marvell that own the custom silicon segment.