So will Fultz be in the running next year? What about Smith after the 2019-2020 season?
Fultz played 14 games this season so no he won't be a rookie next season. Simmons deserved ROY. Coming in like he did playing PG for the 1st time and putting up 15.8 points, 8.2 assists, 8.1 rebounds and 1.7 steals in 81 games while leading the Sixers to 52 wins.
Sure, if he was an actual rookie.
Don't agree with defining a "rookie" as the first year actually playing games. It should be strictly defined as your first year of your first contract. Players like Simmons benefit a ton by being around the NBA game a full year before stepping on the court, which isn't fair. Part of being the rookie of the year is being able to adjust to an entirely new game and lifestyle rather quickly, which gives players like Simmons an unfair advantage, at least in the sense of awarding the top rookie.
I think an argument could be made for Tatum, but Mitchell was the obvious choice to me. I'm pretty confident that Tatum has the best career of those three, but given the context of the differing teams and the fewer touches and usage that Tatum had, you probably have to give Mitchell the nod.