Yeah, that's it. Tank for six straight years until you finally get to a place where you have an outside shot at making the playoffs. That's definitely the way to go.
No, tank for however long it takes to assemble some highly valuable young assets, and perhaps a young franchise star. Then you use those assets to put together a competitive team, along with free agency and whatever else is at your disposal.
You need that foundation first, though, and the foundation is always built with high draft picks. That means being bad for a couple years, at least.
The Timberwolves are an exciting, talented young team, but I wouldn't use their method of team building as a model for how to build a champion.
No NBA champion in at least the last 15 years has built their championship squad by missing the playoffs for 6 straight seasons to build up assets. Of course, you need assets and when you do get into decent draft position, you need to be a combination of lucky and good to find the right talent.
By your preferred method, the Kings, the Pistons, the Wizards, the Nets, and the Bobcats should all be knocking on the door by now.
Being bad on its own isn't going to guarantee that you will become competitive. You have to draft well, develop well, and make the right moves. Plus, you need a good coaching staff to make the talent work together.
My point is that getting those high draft picks is the necessary starting point. A lot of teams are bad each year, but only a few organizations are good enough from top to bottom to work their way up from the bottom. Some bad organizations hit the jackpot in the lottery and jump to the top really fast -- but they often are bad for a long time before that.
The bottom line, though, is that you're not ever going to have a true contender unless you tank and draft high. It just doesn't happen. There are maybe 2-3 exceptions over the past 40 years.
The Kings, the Pistons, and the Wizards, at least, have assembled a handful of very valuable assets over the last few years. Whether they can develop those assets into competitive teams in the next few seasons will depend on how well managed they are, what they do in free agency, etc. But because they've drafted high they have the raw resources.
The Nets would be in such a position if they weren't so desperate to be competitive right away that they keep trading away their future for their present. The same can be said of the Bobcats. That's the real ticket to long term mediocrity -- mortgaging your future for the sake of being better and more exciting right now.