This is because people keep buying the gimmick pairs like crazy, therefore driving the company to focus more on that aspect of their line.
Besides, they already have a well established line of "normal" denim. It would be redundant for them to come out with more "normal" stuff when they already have a solid selection. Makes sense to me.
I have a nudie jacket and it is about the same quality as N&F. I would actually say the quality is a bit better than APC, but keep in mind this is from their high end line and it was a $225 piece.
Their selvedge is a little overpriced for what it is though. They want $270 for jeans that should realistically cost $200 or even less. I am aware they have a lot of fits. But at that price point you can get into Baldwin/Telleson/3sixteen/Momotaro territory.
You do realize Nudie is imported and made in Italy, right? It is not overpriced for the USA market. Those other brands are domestic and you are not paying the same duties/shipping costs that are billed into the product on those items. Momotaro can be a bit different because they are the denim mill, label, desiger, and producer so they can achieve a better price overall than pretty much any other label.
As for N&F, they are creative and it is great to see a brand try to do something different. If you want a normal indigo denim, there are plenty of options out there, but for me personally, I want to wear the N&F denims that are different.