A lot of people seem to subscribe to the theory that all you have to do is throw some young players together, and they will automatically "gel" in a couple of years and become a good team. If you believe this, then it makes sense to invest in the likes of Dragic or Beasley or Gordon, because even though those players may look marginal now, they are on the right path to becoming leaders of a good team.
Unfortunately, it doesn't work that way. Only a few players are going to grow up to take their place among the league's elite. If you can land such a talent, through the draft or after the player is in the league, then you pay any price to make it happen. But to invest heavily in players who are doomed never to reach the first tier is to build a roster that, by its very construction, has almost no chance of contending.
Does anyone really think that Dragic is going to be a top-five PG in this league, ever? If so, which player of his generation is he going to surpass: Paul, Williams, Rose, Irving, or Rondo? And can he hold off the next wave of upstarts in the meantime?
Now, Dragic isn't paid like a top-five PG, so it's not the end of the world if he winds up as only an average starter. But he provides a good example anyway, because he's the level of player that you can't afford to invest too heavily in if you are trying to form one of the league's top teams.
Beasley is young enough that it's unclear yet who his peer group is. I certainly wouldn't say that it's likely that he becomes a top-five SF in five years, but I can't immediately identify five players at his position who are virtually guaranteed to be better in 2017, when Beasley will be 28.