PG is defining position in connecting team to the coach.
With modern day "scoring" PGs this became a struggle.
The inability of some PGs who just forwards trapped in PG body to communicate and implement the team strategy on the court leads to all this point-forwards, motion-offense, etc. techniques.
All just to work around missing PG skills on the NBA team.
Some top preforming NBA coaches just cannot do any good without top-level facilitating PG (see

...)
Some managing to adjust by tweaking the system.
To get top level facilitating PG in today NBA in trade of FA is close to impossible.
No team will give it up. They will max up the man and he will have all intensive to stay with established system and coach he already worked together.
To draft one is never a clear cut. This skills are coming to view after many years in the league.
Scoring PG is another story... its much easier to see if youngster with PG body already has it.
So most of NBA coaches forced to work with scoring PGs or a bunch of mediocre facilitators.
Fiz has the second case in NY. After his prior experience it is new settings for him.
We'll see if he can adjust.
"There are more things in heaven and earth, Horatio, Than are dreamt of in your philosophy." Hamlet