Kendrick Lamar is able to manipulate the tone of his voice to convey complex emotions. This allows him to tell a story with multiple personas, which he switches between through use of vocal inflections, voice cracks, and annunciation. This versatility makes the listener feel like they are listening to a diverse group of people rather than one man. Lamar can also manipulate his lyrical choice with vocal range. In light of his undeniable artistic talent, Lamar is the best rapper of all time.
While Kendrick Lamar is an incredibly gifted vocalist, this does not necessarily make him the best rapper of all time. It may make him one of the most versatile rappers, but he has yet to leave a sizable mark on the rap community.