I think you massively overrate Booker then. The 2018-19 team had some talent on it. Ayton, Warren for 43 games, Oubre, Bridges, Richaun Holmes, Melton. Harden gets that team to at least .500. All those guys probably do. Booker couldn’t elevate them at all. I mean, they were 21-61 the year BEFORE they got Ayton and Bridges and the next year they got those guys, they were WORSE at 19-63. His lack of elite playmaking ability is what keeps him from being a great player to build around because he doesn’t elevate others at an elite level.
Booker was just 22 years old in that season. Could Steph lead that team to the postseason or 500 ball at 22? No. The Warriors were awful throughout Steph's first few seasons. Maybe LeBron elevates that team at that age but that's probably it.