The problem is with mathematical notation, not the students. If you step back and look at mathematics from a product perspective, from a tool designers perspective, it's pretty clear that the user experience is awful. Generation after generation of students encounter this tool and say repeatedly, emphatically, "I hate math." and yet we seem blind to the possibility that the tool itself could be improved.
It's like we're forcing children to learn how to use an astrolabe and then blaming them for finding it complex and inapplicable to their daily lives. Google maps provides the answers they want with a better user experience. I would have astrolabe anxiety, I don't have Google maps anxiety.
Unfortunately there is a pseudo-religious connotation to mathematics. It is "pure", "beautiful", etc. Teachers rarely encourage students to change, improve, disrupt, or invent math.
Mathematical notation and pedagogy is continuously evolving and to think that we're at the global optimum right now both ignores the negative reviews users are constantly providing and ignores the history of math itself.