The great challenge of breaking TRADITION (queue up Fiddler on the Roof)
Tradition is an enormous hurdle to overcome despite the fact that there are newer and easier methods, just look at the metric system in the US. Big change is slow and can take generations. Musicians brought up on Traditional Notation, no matter how much they may have suffered to learn it, are now ingrained with it. There is no motivation for learning another notation. Among this group are the gatekeepers to music education, the instructors, and they are unlikely to adopt an Alternative Notation for the same reasons. However, if they can be convinced they can attract and retain more students, then perhaps that will provide the motivation.
Today, if one wants to participate in the mainstream of the music world, one must be fluent in Traditional Notation (with some notable exceptions). So for those who are dedicated to a “serious” path in music are likely going to need to be able to read it.
It’s important to remember that the Alternative Notation movement is not about changing the music itself or even music theory. It’s about simplifying the reading of music so that more people can participate in the joys of playing music. And in the end, does the listener know or care what sheet music notation musicians are using?