I would say 2016 was a worse year for Leeds on the pitch, yet they failed to sack him then. He follows it up with winning the Grand Final in 2017.
Yes they are not playing well and have not won in seven, yet he is still the most successful coach in the Summer era.
We are not privileged to the situation within the club. I understand he was no longer universally popular at Leeds
My thought is that Gary Hetherington who I believe is the reason he kept his job after 2016. Lost the battle with the rest of the board to retain him, therefore he was fired.
I suspect he will not be out of work for long.