No, he didn't invent rock and roll music. "Invent" is such a terrible word when discussing the creation of art. As it is always an accident, an unforeseen set of circumstances colliding gloriously or horribly. By 1955, when Berry released "Maybelline," rock 'n' roll had been implicitly brewing and gestating for a decade. "Rocket 88," by Ike Turner, is widely acknowledged to be the first rock song, but he was preceded by others, notably Sister Rosetta Tharpe. Anyway, who can forget John Lee Hooker's 1948 chestnut "Boogie Chillen," which rocks harder than anything you can name.
If not as the creator, what's his legacy?
Well, Berry emerged as an early rock 'n' roll pillar, and more than any other contemporary—Elvis, Jerry Lee Lewis, etc.—is still a majority contributor to the musical DNA of all of the rock and the roll that followed him and where it has ended up 60 years on. With his jump-blues backbeat and next-level guitar playing, he wrote the alphabet intrinsic to a half-century of culture. Culture that changed ideas and minds and politics. Culture that is so ingrained in all of us it would take lifetimes to sort it out.
As for Chuck's lyrics, that's another story. So perfectly articulate with the slightest turn of phrase he would make up his own words if dictionary ones weren't cuttin' it. The highways, burger joints and thrill-chasing teens that populate his songs are always in the foreground of the draconian social and civil politics of the time, like the shady police in 1956's "Brown Eyed Handsome Man."
That tune was originally called "Brown Skinned Handsome Man," which reveals plenty about the song's intended meaning but even more about Chuck Berry the artist. He was an unabashed capitalist, a true product of his time. He considered his music product, had no interest in particularly evolving it and badly wanted well-deserved hits. Changing what would've been explicit lyrical warfare on despicable social mores at the time with "Brown Skinned" to subterfuge guerrilla tactics with "Brown Eyed" turned out to be the more effective idea for the movement Berry wasn't really even a part of. The characters and situations he portrayed in his songs were adherents to basic western capitalism within the first mass-produced and marketed art form for teenagers ever brought to the marketplace. And Chuck Berry, with his music, foresight, artistry and vision, was a quintessential American.
All these years later, where is rock 'n' roll? Well, it's not a youth phenomenon, it's not particularly commercially successful, whereas other forms of pop music that emerged since are both and more. It's nostalgia. The idea isn't to prop up a corpse or bring it back to life. If Chuck Berry dying is the symbolic act needed to put rock 'n' roll in the ground and start over then his death will be just as meaningful as his life. Because in rock 'n' roll, the whole idea is to keep moving, and outside of small regional scenes, that movement ended a long time ago.