Not sure if you're American, but investment funds in other countries, especially those with "hints of socialism" usually don't put "profit above all else" like is common in America, hence "good enough" is usually just that, good enough.
Seems they're doing exactly what is expected of them, staying around the benchmark index, so that sounds pretty good:
> The fund has outperformed the benchmark index set by the Ministry of Finance by 0.24 percentage point since 1998.
The higher the potential return, the higher the risk.
Let's say Norway invested all the money into a wager on a football game, and they won, resulting in a 100% return. They'd be lucky, and they'd be idiots.
They probably need to maintain fluidity at any given moment, given this is a retirement fund. So no crazy but risky returns in portfolio. And this issue here is likely also about risk mitigation.
Is this poor performance due to this kind of active management?