The problem is that competitiveness in the NBA really requires both luck and skill. Look at the Spurs - model organization, but they got super lucky to get Duncan, and then they got super lucky again to get Kawhi Leonard (in that even if they had identified him (the skill part), they got lucky to find a trade partner that let them end up with him). If they even dropped to number 2 in the 97 draft, what does the recent history of the NBA really look like?
No amount of tanking changes this, and no amount of trying to stop tanking is going to really balance the league competitively. As I've said, I think a lot of this just comes down to owners thinking it's unfair that another team gets something they don't, so they want to try and create "fairness"
As well, the real problem with competitiveness is not the tanking, it's the superteams, both in terms of when stars come together, and in general terms of how long good teams can remain near the top (which in turn, since wins are a zero sum game, keeps more bad teams bad). If this is a problem they need to solve, then they need to work on that too (I don't think it's a problem they need to solve). Institute a hard cap, make it so you can make a bunch of trades without having to worry about the cap until a deadline (i.e. you can go over the hard cap in the off-season but you have to be below it September 1 - July 1), and increase the max in terms of money but decrease it in terms of length. Increase movement of superstars while not letting them all coalesce on the same teams. etc. etc.
But this is why they focus on the lottery even though it hasn't done a thing in any iteration to change competitiveness.