You need to, as IndeedProceed also stated, look at how teams that "earned" a top-5 pick then went on to perform in subsequent years. My threshold was winning a title within 10 years. A more forgiving threshold might be to make the Conference Finals within 8, or whatever. I would also impose the requirement that the particular draft pick actually _contributed_.
I must admit that I don't understand your insistence that we focus on how a team "earned" the pick, or how soon thereafter the team went on to win a lot of games.
I would think both those points are pretty obvious.
If a team is already a strong roster and gets a top-5 pick because of it was the result of a trade, then they didn't have to 'be bad in order to be good'. Detroit won 50 games and was the 1st seed in the East in 2003. They then got the #2 pick because of an earlier trade. They didn't get bad and then win the title in 2004 because of adding Darko.
That's really the preferred position to be in. Get great talent because OTHER teams suck. Hopefully, if we don't trade it, we'll get a great pick with the 2016 Nets pick because, unless something dramatic changes, they look destined to be pretty sucky then. Of course, Detroit in hindsight blew it by picking Darko.
The question that is being tested here is how valuable and necessary being one of the top 5 picks is for rebuilding a team back to title contender status. A team like Detroit wasn't rebuilding.
As for the time threshold, that also should be obvious. The Celtics had the #2 pick in 1986. They won a title in 2008. Does it make sense to associate those events causally? How about Dallas picking #2 in 1994? Did that contribute directly to their title in 2010? Well, the player (Kidd) did. But he spent a long time on other teams in between. What they got back in trade for him (Cassell, Finley, A.C. Green and a future 2nd) sure didn't.
At some point, you have to draw the line and disconnect the pick from the future events. Too many steps in between. Changing GMs, coaches, etc.
If we get a #3 pick this year and get to the ECF within 4 years due to having that player or whatever we traded him for, then that's probably pretty obviously causally connected. If we don't get back to the ECF for 20 years, I don't care how tightly you can couple the links in the chain between now and then, I'm not going to give any credence to the connection.
So a reasonable threshold is probably somewhere in between. Given the length of contracts, 8 years to reach the ECF seems reasonable. And 10 years for a title.
My hypothesis, based upon my limited investigation, is that the overwhelming majority of very good teams acquire at least one of their key players via a top 5-10 draft pick. I don't particularly care whether the team reaches the pinnacle of success in that player's first 5 seasons in the league, or that player's last 5 seasons in the league, so long as the player is a key part of the team's success.
See above for the discussion on why SOME sort of time limit matters.
I also don't care whether a team got that top 10 pick by being bad or by some other method. It's enough for me that the easiest way to get a top 10 pick is by being bad yourself. I'm not interested in entertaining the idea that a player drafted onto a team that is already pretty good is more likely to be successful and realize his potential than a player drafted onto a team that has less established talent or veteran experience on the roster already. Good players are good players, and well-run teams make the most of them, generally speaking.
I don't know how to respond to that last paragraph. I don't see how you can dismiss the difference between the two situations. They are completely and fundamentally different situations for a team to be in.
At any rate, what we've established here is that you are NOT interested in answering the question that IndeedProceed and I were proposing. You are interested in testing some other hypothesis. Which is fine.