Possibly, but I suspect it’s more likely that there’s a cost associated with including HD radio support (perhaps a licensing fee), and if customers weren’t actually asking for the feature or using it, perhaps the bean counters decided to stop spending the money.

Yes, the AM stations are longer range because of their frequency; being down around 1MHz means that the signal can propagate for hundreds of miles.

I’m not sure how lingonberries, which are also quite popular in Sweden (you can get lingonberry soft drinks at Ikea in the US), are more Norwegian than the capital city of Norway....

Also HD Radio isn’t DAB, it’s a protocol for increasing bandwidth over FM.

That you can’t find stations you like has no bearing on whether HD radio blows or not. The technology is one thing; how it is implemented at a local level/your personal preferences another.