The music is consistently inspired by the folklore of the respective countries. The late 19th and early 20th centuries produced a plethora of composers who emerged from flamenco, South American dances, and other genres. There are major schools of guitar playing that have significantly advanced the instrument. Techniques are refined. What Tárrega and various South Americans began is further refined.
Due to a lack of major works, many pieces are adapted for guitar. Tárrega himself is a treasure trove of such adaptations. He mostly transcribed classics. But Granados, Albéniz, and other Spanish composers are gratefully adapted. Albéniz’s Asturias is actually better known for guitar than for its original instrument, the piano. Yes, that’s how far things went and still go…