The '90's was literally the time when the old guard music industry pundits said rap music was going to fade away cuz it was just a fad. Instead it exploded and permeated almost the entire entertainment industry. That's part of what made it so legendary to live through. I took a university course in 2000 on Popular Music from 1950-1990. The readings for the rap music unit on that course included articles such as "Is Rap Music?" questioning whether it was even art and "Rap Fad Has Peaked" predicting its demise. The school hadn't updated their curriculum in 10 years and it was a joke. Now Harvard is building a Hiphop Archive & Research Institute!
Hiphop Archive & Research Institute
So yeah, the era that defied active attempts to thwart rap music is going to hold a special place for the people that lived through it and were old enough to understand what was going on.
A good way to illustrate this is to look at the list of rap albums ever to hold the #1 spot on Billboard's albums chart. I've put the biggest hit from each album in brackets.
1987
Beastie Boys - Lisenced to Ill (yes this was the first ever #1 rap album thanks to U Gotta Fight For Your Right To Party)
1988
NONE
1989
Tone Loc - Loc-ed After Dark (Wild Thing)
1990
MC Hammer - Please Hammer Don't Hurt Em (U Can't Touch This)
Vanilla Ice - To The Extreme (Ice Ice Baby)
1991
Vanilla Ice - To The Extreme (Ice Ice Baby)
NWA - Efil4zaggin (Alwayz Into Somethin)
1992
Kris Kross - Totally Krossed Out (Jump)
Ice Cube - The Predator (It Was A Good Day)
1993
Cypress Hill - Black Sunday (Insane In The Membrane)
Snoop Doggy Dogg - Doggystyle (Gin & Juice / What's My Name)
1994
Beastie Boys - Ill Communication (Sabotage)
Snoop Doggy Dogg - Doggystyle (Gin & Juice / What's My Name)
1995
2Pac - Me Against The World (Dear Mama)
Bone Thugs-N-Harmony - East 1999 Eternal (Crossroads)
Dogg Pound - Dogg Food (New York, New York)
1996
2Pac - All Eyez On Me (California Love)
Fugees - The Score (Killing Me Softly)
Nas - It Was Written (If I Ruled The World)
ATCQ - Beats Rhymes & Life (Stressed Out / 1nce Again)
Makaveli (Hail Mary / To Live and Die in LA)
Snoop Doggy Dogg - The Doggfather (Snoop's Upside Ya Head)
1997
Scarface - The Untouchable (Smile)
Notorious BIG - Life After Death (Hypnotize / Mo Money Mo Problems)
Wu-Tang Clan - Wu-Tang Forever (Triumph)
Men In Black Soundtrack (Men In Black)
Puff Daddy & The Family - No Way Out (I'll Be Missing You)
Bone Thugs-N-Harmony - Art of War (Look Into My Eyes)
Master P - Ghetto D (Make Em Say Uhhh)
The Firm - The Album (Phone Tap)
Ma$e - Harlem World (Feel So Good)
1998
DMX - It's Dark & Hell Is Hot (Ruff Ryders Anthem)
Master P - The Last Don (Goodbye to my Homies)
Beastie Boys - Hello Nasty (Intergalactic)
Snoop Dogg - Da Game Is To Be Sold Not To Be Told (Still A G Thang)
Lauryn Hill - The Miseducation of Lauryn Hill (That Thing / X-Factor)
Jay-Z - Vol 2: Hard Knock Life (Hard Knock Life)
1999
DMX - Flesh of My Flesh Blood of my Blood (Slippin)
Silkk The Shocker - Made Man (It Ain't My Fault Part 2)
Nas - I Am (Nas is Like)
Ruff Ryders Volume 1 (Jigga My Nikka)
Notorious BIG - Born Again (Dead Wrong)
2000
DMX - And Then There Was X (Party Up)
Jay-Z - Vol3: The Life & Times of S. Carter (Big Pimpin)
Eminem - The Marshall Mathers LP (Stan)
Nelly - Country Grammar (Country Grammar)
LL Cool J - GOAT (Imagine That)
Mystikal - Let's Get Ready (Shake Ya Azz)
Ja Rule - Rule 3:36 (Put It On Me)
Roc La Familia - The Dynasty (I Just Wanna Love U)
You can see the momentum building from NWA onwards until rap explodes in 1996 with 6 #1 albums. Before 1996, there would be no more than 3 rap albums at most to go #1 in a year. From then on, 5-8 rap albums would go #1 every year for the rest of the 90's. That's putting a stamp on the industry and destroying the anti-rap arguments that were being made in the 1980's and early 90's.
There were also 8 rap albums to go #1 last year, but that's the new normal.