Really, the Beatles were the perfect combination of assets for greatness that will not surpassed. Vocals, songwriter, lyric craft. Quite beyond the fact that they were in that category of "professional celebrity" , constant fodder for the gossip mills and such, it is the actual body of work they've left us, the songs and the albums they appeared on, that we talk about today , that we play , that we sing, it is their music that new generations continue to learn.
Harold Bloom, the great literary critic, wrote a book called "The Anxiety of Influence ", in which he posits that Shakespeare is the writer who created literature, that complex kind of tale telling that delves into the deepest reaches of the human soul and communicates the contradictions within as a way of understanding ourselves as creatures in the world at large.
He insists, forcefully and convincingly, that the writers that have come after Shakespeare are permanently in his long and endlessly looming shadow, his influence is so vast and pervasive. Even geniuses that have emerged after the Bard remain under the shadow he cast, and even those who have styles, methods and poetics that are antithetical to what Shakespeare created find that they created their methods and composed their aesthetic in response to terms Shakespeare established centuries ago. He argues that Shakespeare set a standard for literary genius and that indeed others have raised to his level of invention, insight, sheer poetic and intellectual genius, that others have risen to the bar he set, but have not "outgrown" the Bard nor surpassed. And it is from other geniuses that have been with us since Shakespeare's era, Goethe, Whitman, Proust, who have written in the shadow of the Master and who cast long shadows of their own over the literary landscape. Younger writers try to surpass or avoid the influence, but is there, in the air, in the psyche, nearly genetic in how the aesthetic is distributed among us. More brilliance and genius will emerge, of course, but the anxiety in the title remains, that each of us who fancies themselves an orginal in some small way are, like it or not, in the debt of someone greater , greatest of all, of whom we prefer not to mention.
The Beatles, to a major degree, are in much the same position as the Bard, which is to say that they absorbed the lessons of both the pop musics of African Americans and a more scattered European sensibility and developed a way of making popular music that was the next evolutionary step in ways that transcend their rock and roll origins. Everything from Carpenters , punk rock, disco, prog rock , rap and dozens of sub genres owe something major to what the Beatles accomplished. I doubt their influence will lessen in our life times.