Building a winner is tough and expensive. Tearing a team down is cheap and it takes long enough to disprove the "building a future winner" mantra that many fans buy into it.
Tanking rarely works from a winning perspective, and usually depends on two factors, only one of which the team can control. Timing of a tear down to coincide with getting worthwhile players is tough to control. The other factor is, to make this strategy work, you have to have an NBA team.
Unless the goal all along was to go cheap. Then it always works...