That's almost certainly not true of most star forwards.
Depends on what one considers "breaking out"... And what constitutes "star player".
Top 20 scoring forwards right now:
MacKinnon (jump @22yr old season)
Drai (from 77/70pts prior to 105 @ 23)
Kuch*
McD
Connor*
Patrnak
Marner
Eichel*
Scheifele*/Rantanen/Keller*
Necas*
Hegel*
Bratt*
Hughes
Crosby
Reinhart*
Panarin*
6 fwds tied at 65pts (Nylander*, Point*, Suzuki*, Stutzle, Robertson, Raymond*)
I'm working from assumption that top 20 in scoring = "star" (very fair to argue it's a smaller, or larger #, and to argue there are "star" forwards that might score a bit less but contribute in other ways.. have to draw a line somewhere & Im sure if one changes the cut-off it will have some impact on the ratio...)
Before looking at #'s, I'll randomly assign "breakout" to mean 70pts+ (or equivalent of .85ppg in 65+ game season). Same applies re. Setting a different cutoff...
* = players whose first 70pt+ season (or .85ppg in 65+ game played season) came at 23 or older
So about 14 of 24 players making up the top 20 forward scoring this year saw their first high scoring season come at or after 23...
** Did this quick and dirty, may have miscounted a year here or there, but frankly if it's 22 vs 23 vs 24 I think the point remains relevant...