The whole system seems like a sham to me. If one artist has fans that listen 24/7 and another artist has fans that only listen for one hour a day (but that artist is all they listen to), it should be the same. Each person’s account should have its own “pot” out of the subscription fee that only they can allocate to the artists they listen to. Duration of listening shouldn’t matter at all.
It’s not really a backup X. In any given cell in a woman’s body, one of the X chromosomes has been inactivated into something called a Barr body. The remaining X chromosome is then the active one.
Women carriers of the gene defect for protan (causing protanopia in males) exhibit Schmidt’s Sign, an abnormal insensitivity to long wavelengths (red light). This is due to the highly skewed L:M cone ratio caused by the defective gene.