No disrespect specially to Cousins, but he has a lot of wear and tear already, while Wall is coming off from a season ending injury so we still don't know the extend of the damage.
Honestly, based on what I see, cousins is not anymore as a valuable player as he was before.
After he got traded to the Pelicans, I think he was already battling with injury or maybe he was traded because he was battling already when he was still with the Kings, but respect to this man, he was really making the Kings at exciting team to watch during the early stage of his career, it was just the injury problem that is slowly killing his future in the NBA.
You are not the only one who sees that, it's pretty evident based on the amount of contract he had recently. He was signed for one year deal amounting to $2 million, not the usual salary for a star player because they signed at least $20 million per year. https://www.basketball-reference.com/contracts/HOU.html
I remember Dwight Howard was also a dominant player in his prime before the injury things like Cousins. I think those teams who signed players for a high amount of salary are also gambling with their prospective players because they also don't know whether those players will suffer a major injury which changed the way they play or not.
I think Dwight was a different player since he is more better in defense than offense, and this big guy does not know how to shot 3 point, unlike Cousins where he really developed his 3 point shooting. Dwight now does not earn a big salary as well but once in his life he was able to sign a big contract, i just hope he could come back like his old Howard but it's unlikely now as he is not getting any younger, good thing he will retire soon with a ring.