I posted the following comment on that board. Hopefully there is a response in the future:
Can we play on the streetball courts offline and/or in other game modes besides "The One"? I prefer to play basketball videogames where I control the entire team (5v5, 3v3, etc.), not simply player-locked to a single player. Yet in NBA Live 18/19, all of this great content (the courts, player legends, etc.) is not available for that type of play.
It's odd because the opening game of NBA Live 18 is one where you play basically a game at the Drew League court using NBA players, control your whole team, no player-lock and yet this is the only time in the entire game where you can play in that fashion on streetball courts.
Based on footage I've seen of NBA Live 19, it seems to be following the same design decision as the intro game appears to be a game of 3v3 on the "black" court where you control the team (no player-lock) with Shaq, AI, and Vince Carter.