When you tank you have a terrible roster. You get that one good player but everyone around them is terrible. By the time you build up the roster, their rookie contract is over and they are headed to LA or NY and you are right back to being terrible again.
The teams that stink, usually continue to stink. There are franchises that have been tanking for years and it never seems to work out for them. Maybe they will get there one of these decades.
I would rather get there through trades and FA with a solid core through the draft. That is how good franchises seem to do it.
You have to follow the OKC, Pacers, Early Hornets model and get 3 drafts or more in a row right, with at least 1-2 of the players you get being superstar level players or close to it.