I think the worse the team and the lower the expectations and existing talent the better for a top pick.
LeBron, Durant, Carmelo, Wade, all had that room to grow.
depends on the situation, for guys like lebron, kd, wade, melo and maybe jabari/wiggins they are wing players that you can just give them the ball at half court and they will make things happen. for a guy like embiid who is a post player there needs to be a good offensive system with guys who know how to feed the post, a good pick and roll PG and good shooters so the lane is not too clogged.
there are a few guys who are truly bad players but most busts are busts because they get drafted by the wrong team. of course a guy like KD or lebron is going to be great wherever he gets drafted but for a potential top 25 type player its not like that. switch kyree with lillard and kyree would be the deserving allstar and lillard would be considered overrated right now. put darko on a team that plays him his rookie year and he doesnt lose confidence and maybe becomes a decent nba player. put greek freak on a better team without two other guys who have the same body type and play the same position and he has more opportunities to be great. a major factor to why duncan is the greatest PF of all time is because he was drafted by a smart organization, same with kobe. there are so many players every year that could be great players but are drafted by the wrong teams, and theres nothing we can do about it because 60% of nba teams are trash teams owned by trash owners who hire trash GMs and trash coaches.