There is more to this, obviously but the fact that almost every championship teams have personnels that have won it before whether be it in the coaching staff or just a wise veteran on the roster cannot be dismissed. Since 1980, all teams who won the finals have players or coaches who have won it before (with the exception of 1989 Pistons).
1980 Lakers:
Pat Riley (Assistant coach)
Kareem Abdul Jabbar (Player)
1981 Celtics:
KC Jones (Assistant coach)
1983 Sixers:
Billy Cunningham (Head coach)
Matt Guokas (Assistant Coach)
Jack McMahon (Assistant Coach)
Julius Erving (Player - won as ABA player)
1991 Bulls:
Phil Jackson (Head Coach)
Jim Cleamons (Assistant Coach)
1994 Rockets:
Earl Cureton (Player)
1999 Spurs:
Will Purdue (Player)
Steve Kerr (Player)
Mario Ellie (Player)
2000 Lakers:
Phil Jackson (Head Coach)
Bill Bertka (Assistant Coach)
Jim Cleamons (Assistant Coach)
Tex Winter (Assistant Coach)
Ron Harper (Player)
Robert Horry (Player)
AC Green (Player)
John Salley (Player)
2004 Pistons:
Larry Brown (Head Coach/ ABA Champion)
Lindsey Hunter (Player)
2006 Heat:
Pat Riley (Head Coach)
Bob McAdoo (Assistant Coach)
Shaquille O'neal (Player)
2008 Celtics:
Clifford Ray (Assistant Coach)
Mike Longabardi (Assistant Coach)
James Posey (Player)
Sam Cassell (Player)
2009 Lakers:
Phil Jackson (Head Coach)
Kareem Abdul Jabbar (Assistant Coach)
Jim Cleamons (Assistant Coach)
Frank Hamblen (Assistant Coach)
Craig Hodges (Assistant Coach)
Kurt Rambis (Assistant Coach)
Brian Shaw (Assistant Coach)
Kobe Bryant (Player)
Derrek Fisher (Player)
2011 Mavs:
Rick Carlisle (Head Coach)
2012 Heat:
Erik Spoelstra (Head Coach)
Keith Askins (Assistant Coach)
Bob McAdoo (Assistant Coach)
Ron Rothstein (Assistant Coach)
Dwayne Wade (Player)
Udonis Haslem (Player)
2014 Spurs:
Greg Popovich (Head Coach)
Tim Duncan (Player)
Tony Parker (Player)
Manu Ginobli (Player)
2015 Warriors:
Steve Kerr (Head Coach)
Luke Walton (Assistant Coach)
2016 Cavs:
Ty Lue (Head Coach)
Mike Longabardi (Assistant Coach)
James Posey (Assistant Coach)
Lebron James (Player)
2019 Raptors:
Phil Handy (Assistant Coach)
Alex McKechnie (Assistant Coach)
Kawhi Leonard (Player)
Danny Green (Player)
Patrick McCaw (Player, LOL)
2020 Lakers:
Phil Handy (Assistant Coach)
Lionel Hollins (Assistant Coach)
Jason Kidd (Assistant Coach)
Mike Penberthy (Assistant Coach)
Lebron James (Player)
Rajon Rondo (Player)
Danny Green (Player)
2021 Bucks:
Mike Buddenhoizer (Head Coach)
Darvin Ham (Assistant Coach)
Chad Forcier (Assistant Coach)
Nuggets will only have KCP as a guy with a ring prior if ever they won a championship. But that Denver squad is full of well-disciplined players that don't need much veteran presence.
We do have an assistant with a ring this season (Ben Sullivan) but the rest of our coaching staff lacks experience including Joe himself. Its problematic that our roster have full of young guys that lacks discipline and he maybe part of Ime's crew that will migrate to Houston. It doesn't help that our veterans are only Horford, Gallo and Griffin which themselves don't have any rings.
Maybe Brad will (and he should) find veteran assistant coaches who can share their experience on winning. I think what we are lacking to get over the hump is just mental and coaching thing.