I believe he means that mining has become a job of a few entities (mining farms). Not exactly Satoshi's idea about decentralized peer-to-peer systems.
If you think Satoshi didn't envision mining farms then you are underestimating him
Big players making farms. Sure. Everyone can see that. Specialized silicon that would lead to 1 or 2 large players controlling bitcoin. No.
The intent was a decentralized peer-to-peer system. Failing to adapt the core to that end put bitcoin on a path of greater and greater consolidation that will eventually make it vulnerable to a number things and non-viable. It will be replaced by a version 2.0 that is peer-to-peer decentralized and probably has other fundamental innovations.