The "Golden Age" was the best in hip-hop
It sounds tired and curmudgeonly, you've heard it before, and you're not even sure if it's true, but there are a good number of reasons why screaming "the golden age of hip-hop was the best!" isn't necessarily wrong. On the one, fewer people were able to record in the late '80s and early '90s; those that were getting their records made (let alone distributed) were, in general, a cut above the bedroom hobbyists populating YouTube in the 2000s.
Simultaneously, techniques for producing and rapping were coming of age. Producers whose names now seem ingrained in memory (DJ Premier, Dr. Dre, RZA, Pete Rock, Prince Paul, Marley Marl, the Bomb Squad) were trying bold, previously inconceivable things with samplers and synthesizers. Rappers, by and large, were pushing the boundaries of the basic flows the grew up on, resulting in a wide array of sounds and styles that birthed rap as mainstream America knows it (and to which rap has remained largely indebted). Though the exact dates are often in dispute, between 1986 and 1994, rap blossomed and produced a concentrated burst of remarkable music (to be sure: there was bad music as well, but we've never lived in an era where bad music exists in greater abundance than in the present).