I don't think anyone is saying the want Cousins to be Dalembert, being an "anchor" doesn't just mean blocking shots, it means being the main communicator to the whole team on defense, look at the Miami Heat, they don't have an "anchor" on defense but their rotations and communication are elite for teams in the NBA. This team is notoriously known for not communicating on defense. If Cousins can be that "leader" that gives a crap on defense, talks, and gets everyone communicating as a unit, you instantly improve defensively. Even if Cousins can't jump 5 feet in the air and block shots, he can read his rotations, hold is ground and put his hands up, a 7'0 Cousins with length is still going to alter shots, even if he doesn't block shots, forcing a guard to take an uncomfortable shot is better than having an open lane for a layup like we saw countless times last season.
There is actually a fair amount of that post I agree with, but the key confusion remains: being an anchor is not the same thing as being a captain. The anchor back there really does need to block or alter shots. That's the point. you win games defensively by protecting the rim. The defensive anchor is your backline stopper, the guy who cleans up all the messes.
I actually see so much tripping over teminologies and theory and whatnot in this thread its not clear who actually has divergent assessments and who has divergent terminology. To that end, I want to clear up what I can there by laying out essentially a theory of three distinct defensive roles, and where Cousins could fit.
Role 1
Basic: Man Defender (stops the man in front of him)
Elite: Stopper (locks down the man in front of him)
Role 2
Basic: Team Defender (rotates, shows, switches, calls out screens etc.. may also play passing lanes)
Elite: Defensive Captain (all of above at elite level and sets defensive tone for team)
Role 3
Basic: Shotblocker
Elite: Defensive Anchor
Some examples: Dalembert is a shot blocker/defensive anchor. But not a defensive captain. Brook Lopez is a shotblocker, but not an anchor or captain. Tyson Chandler is rare in that he's barely a shotblocker, but he's a Defensive Anchor and Defensive Captain. As is Marc Gasol. Doug Christie was both stopper and Defensive Captain. Bruce Bowen actually was just stopper, but not a Defensive Captain.
Of those three roles, I think Cousins can definitely be a solid to good man defender in time. But very unlikely he'll be a stopper. I think Cousins can definitely be a good team defender. And on that front I think he may even have the potential to be a great one, although its hard to see him ever so focused on that end to be a captain. But Cousins will never be more than a middling shotblocker, and isn't going to be able to anchor that backline. When Westbrook gets around Grevis for the 8th time in the game, there is just no way Cousins is going to be able to get over and effectively challenge again and again without ending up on the bench with fouls.
Defensive anchors are rare and elite pieces. If I just went around the Western Conference I would say there are only about half the teams even have one:
Portland: no
Sacramento: no
Golden State: Bogut if healthy
Lakers: no with Dwight gone
Clippers: probably not, have shotblocker (Jordan) but not true anchor
Phoenix: maybe, Gortat is poor man's version
Utah: no, Favors is shotblcoker, will have to prove he's an anchor
Denver: no, McGee is shotblocker, too dumb for anchor status
Dallas: Dalembert is low level
Houston: Dwight AND Asik
San Antonio: Duncan
Memphis: Gasol
New Orleans: Davis eventually (last year not really, just shotblocker)
Minnesota: no
Oklahoma City: maybe not. Perkins is a man/help defender, but not a shotblocker/anchor anymore. Ibaka is more shotblocker than achor.