Drake, Minaj both debuted in the past 3 years.
A 50 cent doesn't come through every year that's a rare occasion, having the fastest debut album in musics history. Since 98 we had Nelly, 50, Kanye, Drake, Minaj, Eminem, DMX, Wayne all spread out quite well.
There has to be a #1,
It's like pop fans saying where are Beatles and Michael Jackson
Besides that I think music has a lot more artists with fame cause labels can't control the flow of artists anymore. Someone like Joey Badass might have 100,000 fans all over the world that would be impossible 10 or worse 20 years ago unless the labels wanted it.