The reason for this is most likely the way we have taught maths in the past as a dry, sterile subject with little relevance to life, other than balancing a check book, and with little aesthetic value. A situation that has to change if mathematics is to captivate students' interest and imagination.
For several years I have been advocating for the study of fractals in the elementary school math curriculum and it seems I have an ally in the Common Core Math Standards, at least in the Math Practice Standards section. Math practice standards 7 and 8 both suggest that students need to search for pattern in order to make sense of the world of maths. Talking of fractals I took my son Adnrew to see the movie Frozen last Sunday and there in one of the songs about the ice castle wwas the word "fractal" as she described the patterns the ice made. The study of pattern in fractals could do a lot to help students develop a growth mindset in math class.
And here is a neat website worth watching that focuses on the idea of Growth Mindset Maths.