Reading between the lines of Trainium left out of the announcement says they tried it, weren’t impressed, and wanted NVidia chips instead.
They just didn’t like the chips is the most logical answer. Particularly given AWS has been doing everything they can to pump up interest, and this huge PR release doesn’t even mention it at all. That omission speaks volumes.
Anthropic is moving to Trainium[1], that will free Nvidia GPUs and allow AWS to rent those GPUs to OpenAI.
[1] https://finance.yahoo.com/news/amazon-says-anthropic-will-us...