That is not totally correct. The process works if you can draft a Kevin Durant. There has to be a franchise changing type player at the top of the draft within the first few picks. Oklahoma tanked in Seattle and got Durant which was an obvious choice. The 76ers thought they had one in Embid. They still may have if he plays this season. By all accounts, Saric had a very good year in Europe and along with Okafor they now have a few building blocks. This off season will be the first one where we will see IF the process can work. They have at least three first round picks with the first most likely in the top 2. Again, Saric coming over and possibly Embid playing in 2016-17. They have said they intend to (and they must) take a significant step forward this coming. There are no excuses after this off season not to improve pretty significantly.
I granted you the OKC Thunder. That was a tank job. But go back through the NBA finals of the last decade (I just went through the last 5 finals, posted below). OKC was the only team that got there via tanking, and it worked because they drafted 3 Superstars with top 4 picks.
2015 NBA Finals
Winner:
Golden State Warriors
Key Pieces:
1 Steph Curry - Drafted 2009 Draft (7th overall)
2 Klay Thompson - Drafted 2011 Draft (11th overall)
3 Draymond Green - Drafted 2012 Draft (35th overall)
4 Andre Igoudala - Free Agency July 2013
5 Andrew Bogut - Traded for in March 2012
Verdict: Did not tank
Loser:
Cleveland Cavaliers
Key Pieces:
1 Lebron James - Free Agency July 2014
2 Kyrie Irving (DNP) - Drafted 2011 NBA Draft (1st overall)
3 Trsitan Thompson - Traded for 2014
4 Kevin Love (DNP) - Traded for August 2014
Verdict: Did not tank
2014 NBA Finals
Winner:
San Antonio Spurs
Key Pieces:
1 Kawhi Leonard - Drafted 2011 Draft (15th Overall)
2 Tim Duncan - Drafted 1997 Draft (1st Overall)
3 Tony Parker - Drafted 2001 Draft (28th Overall)
4 Boris Diaw - Free Agency (March 2012)
Verdict: Did not tank
Loser:
Miami Heat
Key Pieces: 1 Lebron James - Free Agency (July 2010)
2 Dwyane Wade - Drafted 2003 Draft (5th Overall)
3 Chris Bosh - Free Agency (July 2010)
4 Ray Allen - Free Agency (July 2012)
Verdict: Did not tank
2013 NBA Finals
Winner:
Miami Heat
Key Pieces:
1 Lebron James - Free Agency (July 2010)
2 Dwyane Wade - Drafted 2003 Draft (5th Overall)
3 Chris Bosh - Free Agency (July 2010)
4 Ray Allen - Free Agency (July 2012)
Verdict: Did not tank
Loser:
San Antonio Spurs
Key Pieces:
1 Kawhi Leonard - Drafted 2011 Draft (15th Overall)
2 Tim Duncan - Drafted 1997 Draft (1st Overall)
3 Tony Parker - Drafted 2001 Draft (28th Overall)
4 Boris Diaw - Free Agency (March 2012)
Verdict: Did not tank
2012 NBA Finals
Winner:
Miami Heat
Key Pieces:
1 Lebron James - Free Agency (July 2010)
2 Dwyane Wade - Drafted 2003 Draft (5th Overall)
3 Chris Bosh - Free Agency (July 2010)
4 Mario Chalmers - Drafted 2008 Draft (35th Overall)
Verdict: Did not tank
Loser:
Oklahoma City Thunder
Key Pieces:
1 Kevin Durant - Drafted 2007 Draft (2nd Overall)
2 Russ Westbrook - Drafted 2008 Draft (4th Overall)
3 James Harden - Drafted 2009 Draft (3rd Overall)
Verdict: Tanked
2011 NBA Finals
Winner:
Dallas Mavericks
Key Pieces:
1 Dirk Nowitzki - Drafted via Trade 1998 (6th Overall)
2 Tyson Chandler - Traded for July 2010
3 Jason Kidd - Traded for February 2008 (re-signed)
4 Jason Terry - Traded for 2004
5 Shawn Marion - Sign and Trade July 2009
Verdict: Did not tank
Loser:
Miami Heat
Key Pieces:
1 Lebron James - Free Agency (July 2010)
2 Dwyane Wade - Drafted 2003 Draft (5th Overall)
3 Chris Bosh - Free Agency (July 2010)
4 Mario Chalmers - Drafted 2008 Draft (35th Overall)
Verdict: Did not tank
You can go back further, but the Lakers and Celtics teams that were dominant in the late 2000's didn't tank to get there either. You can make a case that the Cavs tanked for Lebron, and their current incarnation is based on those failures (I guess?), but that's pretty pointless as he went and won 2 championships elsewhere. You've got a one-time NBA finals runner up to show for tanking. That's about it.