Obviously SGA exceeded expectations but he was at the time considered a high level prospect in the same general range as Tatum was (trade was 2019). They also got Gallinari, a 2021 1st (18 - Tre Mann), a 2022 1st (12 - Jalen Williams), a 2023 1st (18 - Jamie Jaquez), a 2023 swap (not exercised), a 2024 1st (26 - Dillon Jones), a 2025 swap (moved up 6 spots and took 24 - Nique Clifford), and a 2026 1st.
That was the George trade. A week later they traded Westbrook for Chris Paul, a 2021 swap (not exercised), a 2024 1st (12 - Nikola Topic), a 2025 swap with protections (carried over), a 2026 1st top 4 or else 2nd.
They kept Gallinari and Paul for a season and ended up sign and trading Gallinari for a 2nd rounder, but traded Paul and Abdel Nader for another 1st (2022 - 30 - Peyton Watson), Rubio, Oubre, Ty Jerome, Jalen Lecque.
So they traded 2 All NBA players and completely remade their team and won a title 6 years later and now have a very young core that could win multiple titles. Probably couldn't have worked out much better but when you make bold moves, they do sometimes work out.