Ok, I really have to comment further on this:
We have no clue what made Crestina stop singing, but apparently it was back when the kids were little. I see absolutely nothing in the family dynamics that could indicate why she just stopped. My guess would be that her voice just aged more than she would have liked, and she just didn't like the sound of it anymore.
Now take a look at her children. Orion (who I headcanon as the younger brother) is the responsible one, bitter and angry at Starlo, working on their pa's farm. Meanwhile, Star is the irresponsible LARP-er that never grew up or had a family. But why is that? Largely because of Ceroba (I'll go into more detail on that in another post).
Crestina lacks confidence in her singing even tho Solomon seems to think she would still have a nice voice. We don't know much else about her. Solomon is the head of the family, proud of his family, no indication that he isn't content with his life as a farmer, and the only tiny bit of negativity we see about it is that he was apparently worried when the drought happened (as any farmer would be).
So. We have Crestina, who is very loving and kind, but also just a little insecure and unconfident about certain things about herself for reasons unknown. We have Starlo, who is insecure unconfident about almost EVERYTHING about himself. We have Solomon, who is stoic, steady, and content, as well as a good provider and protector for his family. And we have the North Star persona, who is overconfident about everything, but also views himself as the protector and provider for his town.
Ergo: Starlo takes after his momma, and unfortunately, magnified her only bad quality into pretty much his whole personality. North Star, then, may be a subconscious way for Starlo to try to measure up to his pa.
Maybe that's one reason why Starlo was so fascinated with westerns in the first place? They speak with his pa's accent, and the sheriffs and cowboys in those stories are as stoic and strong as his pa.
Maybe Starlo is like, "Aw, shucks, I'll never be able to be like my pa. But maybe, just maybe, I can be like these guys." Never once realizing that the reason they fascinate him so much is because the qualities he's absorbing from them are the ones he admires in his own father.