Pro sports success is cyclical even for the best teams in the world, so rebuilding is always a reality that management has to consider. Even the Miami Heat will be forced to accept their closing window of opportunity within the next 3 years. Do they "blow it up" to rebuild (which also doesn't require "tanking")? Do they tinker around the edges between now and then, in the hopes that they can sustain *some* success as Lebron/Bosh/Wade are getting older or considering their next contracts? Do they land somewhere in between -- pick one of the Big 3 to trade in hopes of again, sustaining some level of success as the rebuilding process continues..
The point is, there are many ways to skin the same cat. None offer guaranteed anything, or they'd be universally used. You guys are arguing, in some respects, semantics. In other respects, the discussion just proves the myriad of options available to try to improve a team.
It all depends where you are starting from, and where you want to end up. How you value the players currently here, how they fit into the kind of team you are trying to build will provide you with your list of assets to move in trades. Then it's up to the GM to move them for pieces that are valued more highly by the front office, or that fit better, etc.
All options require some degree of luck, but I'll agree with those who say "tanking" -- that is, full-sale dumping of assets without replacing them with equal or greater value, in an attempt to lose more games and get a higher draft pick -- requires more luck than any other options, requires less 'management expertise' than the others, and has a much higher risk of failure than the others.