I think one thing that can be said about the list I made above -- very few teams do it through the draft alone. Building a contender requires savvy moves in the draft, trade, and free agency. It also requires luck.
I'd say the trick with tanking (or sucking, if you like), is to find the right balance between going for high draft picks and not totally detonating your infrastructure, reputation with agents and free agents, and "fan capital" to the point that you hamstring your ability to make the right moves apart from the draft and develop the talent you draft.
and I think that's where a number of anti-tanking (or more specifically anti-Philly-style tanking) people such as myself object to the strategy. Time will tell if the all out destruction of the Philly roster pays off but that would require 2 significant factors to go in their favor:
1. most of their high draft picks pan out into great players or look good enough to fool other GMs into thinking they'll be great players and become trade chips. ( this is where a player putting up numbers on a bad team is questioned as to their worth --> are they as good as their numbers or are the numbers good because the rest of the team stinks?)
2. the players that do develop into good-to-great players are willing to tolerate constant losing and the team's openly destructive approach to the roster and not bolt to a better team after they play out their rookie deal and QO season.
Personally, I don't think all of them will stay in Philly. Noel's already played out 2 years of his rookie deal and that franchise will stink for at least 2-3 more. Embiid could be out all next year so that team is what - Noel and Okafor trying to co-exist as twin-towers and a bunch of D-leaguers next season?
If Noel doesn't bolt that franchise, I will be completely stunned. and if that happens, unless Philly can do a trade with Noel, they'll be out that prime asset in free agency and set further back as a franchise.