The thing is Shake stayed ready. And maybe coach Brown telling him that was the kick in the ass he needed. How many times do you just want to prove people wrong. So you work even harder to prove you are better than what people think. I think this is what happened is happening with Shake.
It should be mentioned in the 5 games preceding the NBA trade deadline, at the height of Shake's minutes (around 29 mpg), he was averaging 13 ppg, 1.2spg, 3apg, 3rpg, 87%FT, 41% 3FG, 53% FG, including a 27pt 6ast showing against the Hawks. He has shown he's capable of filling that offensive role that's needed to compliment Ben and Joel, but Brett was satisfied with a trade for a non-shooting combo guard in Alec Burks, so he phased him out. It's honestly baffling to me.