> One can make similar arguments about Bokmål and Sami, but people speak Sami. And I would argue that a lot more people speak "pure Bokmål" than Nynorsk.

Very, very few. I used to, as a side effect of being quite asocial and reading a lot as a child, and reinforced by my dads very conservative dialect for western Oslo despite where we were living (half an hour drive out the other side of Oslo; dialects in Norway are very local - in that span you pass through at least one other dialect area). The dialect differences were significant enough that an exchange student in high school who was speaking close to perfect Norwegian toward the end of the year still struggled to understand me.

But even then, I adopted more and more of the regional dialect over time. Unless you're a hermit it's hard not to. And there are basically no place in Norway where the local dialect is pure Bokmål.

There might well be more people who can switch to speak pure Bokmål than Nynorsk, though, because it is the primary written language of far more people, and so its the easiest to slip into if you want to speak "formal" Norwegian. This was more pronounced before, when there was a tendency to see the written languages, and especially Bokmål, as more prestigious, and so you might hold a speech in Bokmål instead of your own dialect, TV presenters favoured "pure" Bokmål or Nynorsk instead of their dielcts etc. That's thankfully changed