I looked up the recruiting profiles on 24/7 Sports for Wisconsin's starting four linebackers:
-Zack Baun, OLB: 6'3, Redshirt Senior --> 3*, .84
-Chris Orr, ILB: 6'0, Redshirt Senior --> 3* .82
-Jack Sanborn, ILB: 6'2, Sophomore --> 4*, .89
-Noah Burks, OLB: 6'3, Junior --> 3*, .87
This is not an incredibly talented group of guys. They are 75% upperclassmen...but they're not a very talented group. And in addition, they don't have really tall outside guys; they don't exceed 6'3. So there's no argument that they're these big monster hybrid body types that are just freaks of nature.
They're well-coached and well-disciplined. What other explanation is there?