I don't claim this is an original idea at all, because it's too common-sense not to have been put forward by someone (although you never know with the "thinking class"). The basic difference is that popular music makes you want to move your body along with it, whereas art music does not, appealing instead to the emotions only. A Bach fugue possesses your mind so much that you feel almost paralyzed.
Those are idealizations obviously -- some popular music like Bob Dylan does not try to take over your body, and there are some moments in Western classical music where you feel like you're at a pep rally, such as the Turkish style military march in the final movement of Beethoven's Ninth Symphony. (And please don't labor to argue that the "dance" music from the Classical period is first-rate body-moving music. That was not its specialty.)
There is also variation among individuals -- some people are more overtaken emotionally by Schubert than are others, and some people are less able than others to sit still when "Another One Bites the Dust" starts playing.
And of course some music-makers are better at their craft than others -- Beethoven thunders more mind-possessing sounds through the listener than does Haydn, and Billy Idol gets your body pumping and jumping more than The Doors do. And certainly which emotions are targeted by the art composers, and in what way the pop musicians try to get your body to move, vary across artists and their works, but that split in the broad approach remains.
What are the components of this difference? Mostly it is how heavily the rhythm is emphasized, and not just how strongly the strong beats are heard but how prominently the entire rhythmic structure comes through, including syncopation. Following from that, popular music makes much more extensive use of percussion and plucked bass instruments, since the more voice-like durations of woodwinds, brass, and strings instruments (to pick from Western art music) are not brief and crisp enough to be heard as discrete pulses that establish a rhythm.
A good theory explains a lot with little. The emotional vs. motional focus accounts for all Western art vs. popular music, all the way from late Medieval polyphony through Bach through Terry Riley, and from Scott Joplin through Elvis through Madonna. Think of how much the various art music works differ among themselves -- and yet none of them make you want to get up and move. That reached its extreme limit in John Cage's silent 4'33" (well, maybe you wanted to get up and leave, but not rhythmically). Likewise, think of how different the popular music of just the 20th century sounds -- and yet it all is trying to get you to tap your foot, drum with your fingers, snap, and hopefully move your whole body while dancing.
Why haven't the famous thinkers on this topic noticed the obvious? And more importantly, why haven't their readers stopped them and pointed out how silly their attempts are? (For example, the mere restatement that art music appeals to an elite, while popular music appeals to the masses / working class.) It must be that professional thinkers, at least in the modern age, are drawn from the part of the population that has two left feet, that has a tin ear for dance music. Not that they haven't received formal dance instruction. Nobody dances like that to popular music most of the time anyway. Their bodies just do not respond with that sense of possession by the spirit of the sounds. That's why Serious Music Thinkers revile popular music that's specifically made for dancing the most, e.g. disco and synth pop.
In fact, this generalizes to their lack of kinesthetic "intelligence" more broadly, as intellectuals were also last to be picked in gym class as children, and today are in the worst shape within their socioeconomic class. And it's not some handicap of having above-average IQ -- if you got a bunch of doctors, lawyers, and businessmen together, they could probably come up with the right answer pretty quickly, assuming they had had a basic exposure to both approaches to music. These are the smart people who can keep their balance and lift things. It's always important to distinguish between smart people and nerds.
This might also explain why most dancing scenes in movies come off as hokey or forced. The writer and director are probably more of the thinking-and-feeling type than the moving-and-socializing type, so it's hard for them to know intuitively what the carnivalesque dance club experience should feel like. The verisimilitude of Last Days of Disco is the only exception that springs to mind (and I say that as someone who was an infant in "the very early 1980s"). In addition to his lack of caricature, which only an outsider who didn't get it would have employed, Whit Stillman must have provoked further toe-curling and sputtering among serious expert thinkers by speaking good words about synth pop as well (from here):
By the time I was really getting into [disco], I felt it was gonna go on and on. I didn't have to go that much because it'd still be around. By the time I got around to going more, it was all disappearing. And it went really quickly. I think that dance music came back in a nice way around '83 or '84. There was Boy George, Cyndi Lauper, Madonna. A lot of pop music that was fun. But the places weren't the same. There was no longer that mix that everyone went to.
If the lower classes get bored from art music's attempt to only tap into the emotional centers of their brain, the professional classes -- at least officially -- have a suspicious and even disdainful view of music that tries to engage and perhaps over-ride control of their body. Hence the elite respectability of popular genres such as folk, indie, and freer and less danceable jazz styles. (This is just about all they play in Starbucks, with the welcome interruption from reggae.) That explains why art music flourished during the Renaissance and after -- that's when the elite began to become characterized more by restraint and sobriety, a shift that has lasted through today. That is why body-moving music appeals more to a popular than an elite audience.
There has always been a strong teetotaler current within well-to-do American culture, regardless of political views. In fact, the liberal left is perhaps more puritanically scornful of body-moving music than the fundie right citizens who outlaw public dancing. They may not have tried to regulate it out of existence, but they go much farther in demonizing not just the music itself but the people who it appeals to -- escapist, apolitical, trivial, brainless, etc. (unlike the confrontational, grand, and genius Ubermenschen who dig The Beatles, Tori Amos, and Arcade Fire). At least the beat-banners acknowledge the listeners' basic humanity, if only to stress our susceptibility to music that will weaken our inhibitions and tend to lead us to sin.
It was not too hard for John Lithgow to give a humanizing portrayal of the dance-outlawing reverend in Footloose, but it would be impossible for anyone to give a sympathetic performance of some contemptuous indie dork from the Onion A.V. Club or an earnest left-liberal critic of this opiate of the masses.