I don't understand why Washington and Sacramento didn't just wait. There was no risk they were going to lose them and they would've had the benefit to see if both of them were truly worth the max. Based on their play thus far, neither guy has been. Cousins gets dinged more because he's so combustible on and off the court. What good team has ever had a guy like Cousins as one of its top two players? A guy like Paul George probably isn't a max player yet either but his play last season was a lot closer than Wall's and Cousins'.
I read on a Washington blog after Wall signed his extension that that if the Wizards hadn't signed him to an extension early, a team could've made an offer sheet that included an out after two years. But that scenario was ridiculous because teams are not in the business of wasting their time making offers that are guaranteed to be matched. Both these teams threw away the massive control that restricted free agency gave them.
If Sacramento was concerned that Cousins would react poorly not to getting an extension, well, isn't that a sign that maybe's he's not your guy? If a player can't be counted on to perform and behave well in a contract year, then maybe he's not worth it.
For me, mostly it comes down to thinking that Cousins just isn't all that good. He's a poor defender, inefficient scorer, ridiculously slow in getting back on defense because he spends his time pouting at the refs, and a below-average athlete with terrible balance on his moves. It seems like his mercurial nature makes him more talented than he really is. I'm not a huge fan of Greg Monroe either but I'd take him over Cousins easily.