The whole reason you play the game is to win a championship... And “have fun” as my grade 5 coach would tell me, but he didn’t seem to have much fun when we’d lose.
Especially in the NBA, or any professional sport setting; the entire purpose is to build a team which can ultimately win a championship.
Some teams take the path of building around a drafted star like the Milwaukee Bucks and Giannis Antetokounmpo, or Golden State Warriors and Stephen Curry. Some teams sign stars in free agency, like the early 2010 Miami Heat, or also the Golden State Warriors.