According to reports, Cousins' behavior was much better in N.O. and G.S. than it was with the Kings. And it's his injuries, combined with the lack of contending teams with cap space, holding him back in terms of money and employment.
It's incompetence for the Celtics to rule him out without at least bringing him in for a conversation first because, right now, the Celtics 4+5 positions are a hope at best. You're not going to end up paying Cousins so much money that you can't cut his ass if he gets to be too much of a problem. If Stevens can't handle that, after his failure to handle his locker room last year, maybe Stevens isn't cut out for the NBA.
Your obvious attempt to prove (once again) that you are smarter than everyone else, and your anti-Ainge animus blind you to the obvious reasons why the C's chose to give Kantor the mid-level money instead of going after Cousins.
Here are LIKELY the reasons why the C's didn't move on Cousins (btw- note that I admit I don't KNOW the actual reasons, since I haven't been party to any of the discussions on this topic. You would be wise to note this, since in your posts, you make it seem like you know for a fact what is happening. Just sayin'
1. It's all about the money.....and timing.
Cousins is waiting. Waiting it out for more lucrative offers that will likely be coming from others, including the Lakers. Why settle for $5MM/yr short term when you will get multiple offers in the $10MM/yr range from others.
Now it might end up that Cousin's is being overly optimistic about his chances of getting a better deal, but it doesn't hurt him to wait and see, and the C's didn't have the time to wait. They had to move on someone and Kantor was available, but only for a short time.
2. All the myriad reasons that have been given by so many about Cousins' non-talent factors, like injuries, attitude, etc. All things that could have been overlooked if they could have quickly signed him to a mid level short term deal and assuming he would be thrilled to come here. It would have been a low risk, high reward kind of signing. But between the money and the timing it was never a realistic option.
So in the end, I doubt very much that Danny simply dismissed Cousins as you imply. The very logical thought process that would bring one to see that Cousins wasn't really a realistic option should have been clear to you. It wasn't "incompetence", it was common sense.