it hasn't just been lately. these are the shows from 1990 - 2001. Honestly looking back at the last 20 years there have been like 3 decent halftime shows.
2001: "The Kings of Rock and Pop" featuring Aerosmith, 'N'Sync, Britney Spears, Mary J. Blige and Nelly
2000: "A Tapestry of Nations" featuring Phil Collins, Christina Aguilera, Enrique Iglesias, Toni Braxton and an 80-person choir
1999: "Celebration of Soul, Salsa and Swing" featuring Stevie Wonder, Gloria Estefan, Big Bad Voodoo Daddy and tap dancer Savion Glover
1998: "A Tribute to Motown's 40th Anniversary" including Boyz II Men, Smokey Robinson, Queen Latifah, Martha Reeves and The Temptations
1997: "Blues Brothers Bash" featuring Dan Akroyd, John Goodman and James Belushi (also featuring "The Godfather of Soul" James Brown and ZZ Top)
1996: Diana Ross celebrating 30 years of the Super Bowl with special effects, pyrotechnics and stadium card stunt. Finale featured Diana Ross being taken from the stadium in a helicopter
1995: "Indiana Jones and the Temple of the Forbidden Eye" featuring Tony Bennett, Patti LaBelle, Arturo Sandoval, the Miami Sound Machine and stunts including fire and skydivers. Finale included audience participation with light sticks
1994: "Rockin' Country Sunday" featuring Clint Black, Tanya Tucker, Travis Tritt, Wynonna & Naomi Judd. Finale included flashlight stunt
1993: "Heal the World" featuring Michael Jackson and 3,500 local children. Finale included audience card stunt.
1992: "Winter Magic" including a salute to the winter season and the winter Olympics featuring Gloria Estefan, Brian Boitano and Dorothy Hamill
1991: "A Small World Salute to 25 Years of the Super Bowl" featuring New Kids on the Block
1990: "Salute to New Orleans" and 40th Anniversary of Peanuts' characters, featuring trumpeter Pete Fountain, Doug Kershaw & Irma Thomas