And? The government has declared itself to be a hands off shareholder...

The government declares itself a lot of things until it declares itself something else. I'm not saying it's bad. I'm saying that implying it's entirely privately owned is a bit misleading.

Given the number of debacles involving both Telenor and DNB mismanagement in recent years, one would have thought there would have been plenty of opportunities for the government as shareholder to take action. But so far none of that has materialized...

Remember that the government ownership of large chunks of DNB was a result of the bank crisis. And it's not the first time a Norwegian government has taken over banks and managed them. E.g. if you're old enough you might remember the bank takeovers in the late 80's, including Christiania Bank og Kreditkasse ASA - the same crisis also created DnB when DnC and Bergen Bank was forced to merge to survive.

Norwegian governments have decades of history of extensive interference in the markets (and today control ~1/3 of the value of the companies on the Oslo Stock Exchange)

Again, I'm not saying this is necessarily bad - it's generally worked well, and it's worked well probably largely because there certainly is tradition to stay hands off when possible. And during crises give them enough rope to either save themselves or hang themselves first - no politician wants to step into the middle of a scandal and risk being tainted...

At the same time influence can be subtle - because Telenor knows what is politically acceptable, they'd be highly unlikely to do anything that'd create political pressure to interfere. That can be as effective as direct control.