Yes, you could be.
Depends on your definition of "couldn't get off the bench," but your errant thinking is the same as what Sloan had about player development. Players from Kobe on down need on-court playing time to develop. Kobe averaged 15.5 MPG across 71 games in his first year and 26 MPG in his second year. Bryant shot less than 42% in his first year and less than 43% in his second year. Then, in his third year, after more than 1000 minutes of court time, his shooting started being legit, never returning below 43% in any year.
Bigs are also very in need of playing time, and I am optimistic that this coaching staff (if there ever is a coaching staff again) will do better at understanding that than the Sloan regime--not that the bar has been placed very high.
. . . unless Hayward would've developed faster if he had gotten consistent PT throughout the season (not that Raja Bell and CJ were consistently demonstrating significantly superior performance to Elder Hayward).
Did Hayward earn his minutes, or maybe, just maybe, did it have something to do in part with coaching philosophy, as evidenced by Hayward being granted at least 10 MPG in 11 of the first 12 games after Corbin took over, vs. a maximum of 5 ten-minute-plus games in a row under the reign of Sloan? I say the latter had something to do with it; consistent with my mantra, Hayward averaged less than 10 minutes per game (including DNPs) under Sloan and 24 MPG (including DNPs) under Corbin.
Such a leap is more than "earning" it or improvement (or the effect of losing D-Will). It is influenced by a focus on giving him the minutes (perhaps more than necessary) to develop. And in the last game of the season, he finished off with 34 points. Very reasonable to infer that he might've had more big nights (just like Fesenko holding serve vs. the Lakers in the playoffs but not having received the court time to be more of a force) if he had been given the PT earlier in the season also, especially given that he started the season with three decent games of ~15 minutes to 25 minutes and then had only two games of >10 minues in the entire month of November. Typical Sloan inconsistency in player management.
I'm glad that the future looks brighter in that regard, but the superior choice was to graciously wave Sloan goodbye years before and then hire Carlisle or Thibodeau or someone else when they were available.