> What did he claim that he didn't achieve?

Connections to his work are often vague. Yes, his lab tried something in the same extremely general direction. No, his lab did not show it actually worked or what part of the broad direction they went in actually worked. So I am not gonna cite Fast Weight Programmers when I want to write about transformers. Yes, Fast Weight Programmers also argued there are more ways to handle variable sized input than using RNNs. No, I don't think the idea is special at all. The main point of Attention is all you need was that removing something of the then mainstream architecture made it faster (or larger) to train while keeping the quality. It was the timing that made it special, because it successfully went against mainstream and they made it work, not the idea itself.