Are those games in 1st person? If not then they are irrelevent. Comparing Skyrim's 1st person combat to any other game that is only 3rd person is pointless. Aplles and oranges.
Mount and Blade does have first person as for War in the North... honestly don't remember been a long time since I played the game. At any rate surely you see the point? I was giving examples of RPGs with great combat systems. I'm sure you can find a lot of first-person ones that do. A game being first-person does not automatically rule out great combat.
It is relevant. Think about how much time goes in to making the game already. Now think about how much time it would be to make a complex detailed combat system on par with games that focused on combat. You say there's no excuse for an rpg not to have great combat. (I still say TES combat is) I say there's no excuse for an rpg not to be as big and detailed as Skyrim. See? It doesn't work like that.
With the time, money and resources being pumped into a title as massive as TES, I can expect a good combat system. Both games I mentioned happen to be made by small/medium-sized studios. As for your last point, it makes no sense; there are different types of RPGs. For example Skyrim and Mount and Blade are open world while War in the North is not. It's different genres. Combat however applies universally; it's either good or it's not. And the amount of "detail" in Skyim can be argued (though I prefer not to pick at this aspect of the game).