I hate tanking but I think I've figured out a clever way to punish perennial losers without overly punishing a good fan base for teams who have come on hard times. It comes in two parts, the first is directed at the owners and the second at the team, (sort of.)
The first is for the lottery teams to lose national tv money after consecutive sub 500 (or you could lessen the amount to sub .333 winning teams or any amount that seems reasonable.) This hits some of the owners where it hurts so they try harder. It also will help push out bad owners. Maybe you make it three consecutive years, the numbers can change but the idea is you hurt the owners by costing them money.
The second is by having consecutive non-playoff seasons players on that team are granted an opt-out clause with possible contracts they can sign matching what they have now at a percentage that is in line with how bad their teams were.
We can call the teams lottery teams but there wouldn't be a lottery, worst team gets first pick. But their players CAN all opt out of their contracts at a certain penalty to sign with another team for the same amount of years.
So lets say the worst team was the Sixers, Noel could opt out of his contract and sign a similar contract with another team at a penalty of say 5%. Could be 10%. Whatever the number is that dissuades people from leaving unless it is a particularly bad situation but enough so that players WILL leave if teams are bad for long enough. Maybe you make it for players who have 2 or 3 years of service only.
Then the second worst team is in the same situation only their players can leave at a 10% or 15% penalty. The third worst a 15% or 20% penalty and on and on. Teams that either made the playoffs or hit a certain winning % would be immune.
This way teams that are trying to game the system and really punishing their fans because you don't know if it will ever work out, might get a great player or they might keep losing great players who don't want to keep losing. There would be incentive to winning in that you wouldn't lose any of your players, although most would probably stay anyway for the money.