While individual defenders are nice, ultimately it comes down to team defense.
The Kings actually led the league one year in FG % Defense (which matters more than points allowed) despite having a pathetic defensive PG Mike Bibby and also sub-par defenders like Vlade and Brad Miller. If a team full of those slow-footed lateral-movement stiffs can lead the league in FG% Against that tells you all you need to know about the importance of a good defensive scheme.......and maybe a little luck. I still don't know to this day how that team achieved that with a sieve like Bibby guarding the point.
You have your years mixed up. Our defense died during the year to which you are referring (2003-04).
We led the league in FG% defense the year before (2002-03), and that was not an accident: that was the year we scooped up Jim Jackson (excellent defender) and Keon Clark (our best shotblocker of the Sacto era probably) at the end of free agency. We had BJax and Christie and Pollard (once he got back) and Jackson and Clark and Hedo (a good defender at the time) and Gerald Wallace deep on the bench. Webb still had remnants of his athleticism and shtoblocking ability. We had a LOT of good defenders on that team. And not surprisingly it was the best team of the Sacto era. Better even than the 01-02 team. It just was felled by injuries.
In any case, you can carry a number of soft defenders on the team, but you need them to be surrounded by strong ones.
The next year we let Jackson and Clark go, we traded Hedo and Pollard to get Miller, BJax got hurt, Webb was gone and returned a shell, Christie started to fade, and our defense collapsed. We still had all our soft defenders, including a couple of new ones in Miller and Songaila, but we had lost all the strong defenders that had made us great the year before. I still remember Adelman hinting at that in training camp of that year, noting how we had lost length and nobody could tell him this was the same team despite all the familiar faces. And then we dropped precipitously in defending stats across the board.
2002-03 Strong Defenders: JJackson, Clark, Turkoglu, Wallace, Pollard, Christie, BJackson, Webb (pre injury)
Opp Pts: 95.3 (NBA Rank: 15th)
Opp FG%: .420 (NBA Rank: 1st)
Opp 3pt%: .320 (NBA Rank: 1st)
2003-04 Strong Defenders: , Wallace, Christie (aging), BJackson (hurt)
Opp Pts: 97.8(NBA Rank: 25th)
Opp FG%: .454NBA Rank: 26th)
Opp 3pt%: .339 (NBA Rank: 10th)
And that is the same coaching staff, the same veterans (amongst the poorer defenders), same defensive system. But we lost our defensive personnel, and the results went with them.