Nobel prize for literature has awarded 5 decent winners post-1990. Mo Yan in 2012, Herta Muller in 2009, Gunter Grass in 1999, Szymborska in 1996, Octavio Paz in 1990.
Aside from those 5, it's been decidedly mediocre writers.
Bob Dylan winning a prize for literature is an absolute farce. But no more so than Toni Morrison or Patrick Modiano