2015-16 72 games , 2016-17 66 games , 2017-18 48 games
With that stats, that is not helpful to any team, although in the later season his points averaged has increase.
This is why a lot of hardcore Knicks fan are so mad with the management behind it.
Porzingis stats was not that bad. There are worse things that happened with other players out there.
Plus, you can never have that kind of tall guy again with a great shooting capability and defensive awareness.
This kind of guys are rare. Nowitzki and Durant, that is why these two never got a lower salary. They are super rare.
Maybe it wont happen again in the next 10 years to have that kind of unique player.
Why let him go for this:
Dennis Smith Jr., Deandre Jordan, Wesley Matthews
Porzingis can do what this three can, maybe better and it will just be one seat for the entire roster.

They might be done with the experiment on Porzingis, and they want to try another experiment.
With how the management treat him, I think Porzingis deserves to play in another team, but this player is not extraordinary like Dirk, and the stars that have won championship already. I think him being in the Dallas Mavericks will make him more valuable as he already have Luka who can also generate points for the team, and we have to remember that these guys are still young, there's still more years ahead for them to improve in the NBA.
Dallas has a great chance also of getting into the playoffs in the season to come.