re: Go, I did wonder if there was any connection to Russ leaving (https://news.ycombinator.com/item?id=41132669)
In this case I expect it's more related to how the engineering ladder has changed at Google over time, and the effects of cost cutting placing pressure to conform to the ladder, even when the ladder doesn't reward what it necessarily should be rewarding.
That's about as unobtuse as i can be about it, for various reasons.
In my August announcement, I was careful to say I wasn't leaving the Go project. I'm still involved with the Go project and expect to keep being involved. I'm just not officially on the Go team at Google anymore. Stepping back from the actual team to give others room to lead always seemed to me both likely and appropriate.