To go along with this, the success of the players in the draft is also random and not always a lock. Even if the C's tank and miraculously land the #1 overall pick, there's no guarantee Wiggins, Parker, or whoever pan out. I know that's a negative way of looking at things, but we really don't know how their games will translate to college and the NBA. Flushing the roster for a chance just seems excessive.
I like this chart which shows the success of first round picks the past 30 years -
http://i.imgur.com/Pg5szdQ.pngObviously most MVPs have come from the 1st overall selection, but you still have duds like Kwame, Bargnani, and Olowakandi. Then the 2nd overall picks just fall off the map. None of the other rounds produce consistent all-stars with the possible exception of the 3rd round. You're just as likely to score an all-star with the 10th overall pick as you are with the 2nd pick.
So really, it comes down to talent evaluation. The Pacers have had good success evaluating talent lately. They got Paul George 10th overall (max player), Roy Hibbert 17th overall (max player), Danny Granger 17th overall (was pretty good), some other role players in the 10s, and now have arguably a championship contending team in a small market, with absolutely no draft picks above the top 10 since 1989.
Whereas on the flipside, you have teams like the Bobcats and Kings who have been fighting for top selections for years now, and have nothing to show for it except a character-plagued DeMarcus Cousins.
But Wiggins, right? Ok, ok. Even if he is the next Lebron/Jordan/Kobe, here's the problem - you still need a supporting cast. Like the OP brought up, Tim Duncan is the only #1 overall pick to win a championship with the team that drafted him (past 20 years). Duncan was dominant back in his day, but he had the likes of David Robinson, Tony Parker, Manu Ginobili, and a very complimentary cast of role players with him. Not to mention a HOF coach.
The other #1 overalls had nothing like that. Lebron's best teammate was Mo Williams. Dwight's was Jameer Nelson. Iverson had... Eric Snow? At least Blake Griffin has Chris Paul, but it remains to be seen whether Griffin is truly a difference maker.
Then there are others who get injured before their potential is fully tapped: Bogut, Yao, Oden, Larry Johnson, and who's really sure about Derrick Rose now?
Basically, you can tank all you want, score the #1 overall pick, select a superstar, and still have no championships. Just like the Magic, Cavs, Raptors, Bucks, Wizards, etc. The whole process is a total crapshoot.
As this thread suggests though, the C's can still field the team they have now, not finish last, and win a top 3 pick. At least then that player will be landing on a team with a good foundation consisting of Rondo, Green, and Bradley, as opposed to a team without them, and having to build from the ground up.
Or they could end up with the 10th overall pick and draft a Paul George or Paul Pierce caliber player. Who knows.
I know I kinda went off-topic, but I'm tired of the tanking talk. I understand why people like the idea, but I feel this thread is a good counter-argument. We're more likely to get a Chauncy Billups and Ron Mercer than we are a Tim Duncan. That's just how the lottery balls work.