ESPN.comIn the annual survey of rookies, only 5% of the Class of 2019 thought Zion Williamson would have the best NBA career. Cam Reddish was top vote-getter with 19%.
https://www.espn.com/nba/story/_/id/27421425[https://www.espn.com/nba/story/_/id/27421425/rookies-see-reddish-not-zion-having-best-career]
Based on the results since 2014 listed in the article, we can see that rookies are bad at projecting who will have a good career.