The most ubiquitous name in pop music today isn't, arguably, Taylor Swift or Ariana Grande or even Grammy king Sam Smith -- it's a name that first caught the public's attention back in the 1960s. Yup, Paul McCartney is kind of everywhere these days.

You know that Beatles song "When I'm Sixty-Four"? Yeah, well, dude is in his 70s now and, judging from his schedule, fans definitely still "need" him. (As for "feeding" Paul... he might be on his own there.)

Not only did he collaborate with Kanye on the track "Only One," he also worked with 'Ye and Rihanna on "FourFiveSeconds," performing it on the Grammys stage in February. AND Wednesday (March 25), it was announced that dude will be headlining Lollapalooza.

We may joke that the younger set are wholly unaware of who, exactly, McCartney is, but his resume is beyond impressive in 2015. In light of Sir Paul's latest music world coup, we spoke with musicologist Joe Bennett about why, exactly, McCartney has managed to endure for so many decades.

Why are we still into the Beatles today?

Joe Bennett: The Beatles effectively invented many of the conventions of popular music. Before 1962, very few artists wrote their own music -- even Elvis relied on professional songwriters to supply him with material.

And, of course, they were massive innovators technologically and musically. There are so many things in popular music arrangement and production that we take for granted now, such as vocal doubling, automatic double tracking, phasing, multi-track tape synching, twin lead harmony electric guitar or textural mono-synth lines. In every case the Beatles were either first to try it or were early adopters.

But I think the main reason we’re still hearing songs like 'Yesterday' on the radio, 50 years after they were released, is that Lennon and McCartney understood songwriting on a deep experiential level. They were working from a template inherited from 40 years of songwriting expertise. They then applied all of this musical understanding with an exciting rock sound and brought it to a massive teenage following.

Why does basically EVERYONE like the Beatles?

Bennett: Here, I think it’s mainly about melody. If you ask anyone to name a Beatles song that they like, it’s probably going to be one that the listener can sing easily. If you really listen to their recordings, by the production standards of today, they’re not as good a listening experience as a really well-produced 21st century single.

But when we recall the band’s finest moments we’re not remembering those things –- we’re remembering the melody and the lyrics. And those traditional songwriting skills, which they had in spades, don’t become dated in the same way that music production values do.

So why is Paul basically EVERYWHERE right now?

Bennett: First, I think his gift for melody hasn’t diminished at all. Some music fans denigrate his material for being too nice, too twee, and lacking an edge, whatever that is. But he is also the man who wrote 'Helter Skelter,' one of the most powerful heavy rock tracks of the 1960s. 'Yesterday' itself is one of the most covered songs in popular music history. And I don’t know how can anyone listen to the melody of 'Here There and Everywhere' without weeping with joy –- it’s exquisite.

And second, he’s a natural collaborator. Over the years McCartney’s written or performed with Elvis Costello, George Michael, Lulu, Michael Jackson, Stevie Wonder, Carl Perkins, the Beach Boys and Tony Bennett -- so he’s used to working with people of different eras and generations.

In terms of temperament, McCartney always seems to serve the song rather than his own ego, and his collaborators know that he’s musically so versatile that he’ll be able to add something creatively without overshadowing the artist’s own identity with his own. That, for me, is the mark of a great collaborator.