Rap is in a new golden era
The progression of music will always be weighed down by periods of stagnation. Although new rap acts are presented into the mainstream every year, the actual newness of the music is generally overstated. The prime exception to this rule is the so-called "golden ages," pockets of time where innovation is rampant, and from this innovation comes new styles, movements and sub-genres that maintain the genre until the next radical paradigm shift arrives.
There is debate as to whether there were one or two distinct golden ages, but from the mid- to late-'80s to the early- to mid-'90s is generally considered the period in which rap made unprecedented progression. From the first massive popularization of rap with Run D.M.C. came new ears and new perspectives on the form and an army of crate-diggers to uncover the most potent musical snippets on wax.
With N.W.A.'s Straight Outta Compton came gangsta rap, rap's most successful and popular offspring. While N.W.A. was arguably the most important act in terms of bringing gangsta to the forefront of rap, it was the albums like Nas's Illmatic and Wu Tang Clan's 36 Chambers in New York, Dr. Dre's The Chronic and Snoop Dogg's Doggystyle in California and the Geto Boys' We Can't Be Stopped in Texas that not only solidified gansta's place in rap, but allowed it to diffuse across the most influential rap scenes in the country in a pre-Internet industry.
At around the same time, the Jungle Brothers were one of the progenitors of what is now called alternative hip-hop, so called mainly because gangsta rap took over the industry so authoritatively that any other musical style was secondary.
In quick succession, the Jungle Brothers were followed by acts like A Tribe Called Quest, Pete Rock and CL Smooth, De La Soul, Brand Nubian and others that took the Jungle Brothers' positivity, put their own spin on it and helped develop the subgenre into the perpetually underground scene as it has existed for the past fifteen years, during which it's hard to say that rap has experienced a period of growth like the golden age.
In recent years, there's been dramatic influx of rap emerging that sounds quite different from everything else being made, whether it's the EDM-inflected Danny Brown, the bizarrely political Kanye West, the conscious yet commercial Macklemore, the good kid from the m.A.A.d city Kendrick Lamar, the READ-MY-FUCKING-DIARY confessional Tyler, the Creator, the tweaked-out and jazzy Chance the Rapper, the modernized revisionists A$AP Rocky and Joey Bada$$. It is inevitable that there will always be innovation in anything at anytime, but to have so much variation see commercial success at once is unprecedented in modern rap.