Rarely is the pg in the NBA now a days the leader on the court. The model has evolved.
Not sure I agree on this one.
I think what has evolved is the role a PG plays in todays NBA. As you said guards are primarily scorers now and not mere playmakers. The pass first PG is more or less a relic of the past.
But has the role of the PG as the decisionmaker of the team really changed or is it just, that guard scoring is so effective nowadays, that most PG's decide to score more often than not?
In most cases it's still the PG, who brings the ball up the court and initiates the offensive action. In most cases it's the PG, who handles the ball the most. When we take a quick look at the Player tracking stats at NBA.com the guys leading the time of possession category are guards + Lebron/Giannis. Dc (5.3) and Ty (4.7) lead the Kings in that category by a relatively wide margin.
Why do they lead the Kings in that category? I think because they bring the ball up the floor (notice DMC does that quite a bit too resulting in a suprising 3.0 in that category, which is higher than any other big man) and because they are supposed to run the set plays from the top. So in the end they are the guys, who make the first and most vital decisions for our team on offense and whose responsibility it is to orchestrate our offense. Wether we call that leadership or decisionmaking is just a semantic problem and I'm not very good at discussing semantics.
So in the end I think the phrase of the PG as the "coach on the floor" or "the right hand of the coach" hasn't lost its relevance. The PG position may be the most important position in todays league and for most teams it's the PG, who more or less dictates the way they play.
Thanks to DMC skillset we depend a bit less on our PGs, but sometimes their indecisiveness and problems to orchestrate our offense hurts, leading to those dreadful 1vs1 plays late in the clock, that have lost us more than enough games by fueling the opponents transition game due to our own ineffiency.