. It's seems as if Rosenborg just had a few down years. 2-3 other teams not managed by Ole, not called Molde also won the Norwegian league during that period.
Molde also won the league
without Ole in 2014.
Molde are joint top of the league now (just about) with single-team-league team Rosenborg closer to relegation than the top.
In fact if we take a closer look at Molde's league positions we note that the 2014 win achieved far more points.
Ole lost 6 games out of 30 both times he won the league. Skullerund (Ole's replacement) outperformed Ole and only lost 3 games when he won the league with Molde in 2014
with a league points record.
Looking at the final league tables in 2011 and 2012 Rosenborg underperformed although they did so to a lesser degree in 2012.
I should also add that it is easier for a 2nd team to win a "one team league" when the main team has an off-year because there is less competition from other teams. It's harder in an "n-team" league like the EPL for an over-performing underdog as normally there is another member of the to 6 ready to step up..
So no, Ole achievement isn't as special as you and many on here are making it out to be. It was surpassed by a rookie manager just a scant 2 years later.