Because “new music” sucks.
I recall an interview with Don Henley from over 20 years ago when asked about rap/hip hop music. He said something to the effect of is a performer really a “musician” when they cannot read or write music, cannot play an instrument, don’t sing and “barrow” (or “sample”) music from a real musician’s published song as the basis for their song/music.
So, yeah, “new music” sucks.
Many guitar players don't learn to sight read music. The guitar is a two dimensional fretboard and they learn shapes for chords and scales and they have a specific guitar notation tablature some use in leiu of sheet music.
For example Glenn Campbell was an amazing guitarist, member of the legendary "Wrecking crew" of session musicians that played on a gigantic assortment of top hits of the '60s (Monkees, Motown, Beach Boys, etc etc) and then a pop star in his on right. He never learned to read music. So Mr. Henley maybe ought to loosen his standards on that one.