A lot of the developments of AI in different companies Hinton was not directly responsible for. Hinton never had anything to say about those companies, I don't think he's vying for limelight.

The fact that he never said anything before and the fact that he's saying something now means two things in my mind:

   1. He is noticing  something different about the current iteration of AI technology. We crossed some threshold. 

   2. Hinton is being honest.