Frank Kogan

Anything I'd say would be speculative, since I've done little research and I only consistently follow the Korean charts and the U.S. Top 40. According to Wikip, Gaon doesn't include airplay statistics (maybe doesn't trust 'em). As far as I know, the Brit singles chart has never counted airplay (I don't know if it's started counting streams; in the past it was sales only).

Not counting airplay suppresses the impact of adult consumers and album artists on the singles chart.* Whereas in the U.S., not only is airplay part of the formula, it's also the major window into what's going on in specialty markets like country, R&B, adult contemporary, rock, and so on. And there's often a time lag between what a song does in a specialty market and its crossing over to the Top 40. Presumably a song by Blake Shelton, who's also a TV personality, will cross from country to Top 40 faster than a song by country newbie Tyler Farr.

Again, I'm being speculative; but the Korean music industry is event-oriented to an extreme, which probably means it's teen-oriented as well (though OST tracks, which I assume (w/out knowing) are timed to TV airings, probably get adults but are also event-oriented). Adults are less urgent in their entertainment consumption.

In the U.S. there are different trajectories depending on the artist. Pink, whose audience is now mostly grownups, almost always has a slow build on her singles. Whereas the recent Eminem single jumped to the top 5, then fell a bit, and is now holding steady and could even rise again as people decide they like it (though that's something I'm failing to decide). The Paramore track may be a bit of an extreme case: the group is middling in popularity, so the song's initial fan surge wasn't going to get it into the Top 40. But "Still Into You" is especially distinctive, and so it subsequently got a slow build from casual fans and people previously indifferent to Paramore. That's my guess, anyway.

I do track what gets into the U.S. Top 40, and over the past ten weeks about three singles per week (2.8) get in that hadn't been in before; these mostly break in between 30 and 40. So in that sense the U.S. pop market isn't very inviting. But countering that, there are a significant number of performers who are relatively new to the U.S. Top 40 (Avicii, for example), on their first or second Top 40 hit here. Except I haven't really researched this, so I can't say for sure. I know that in Korea over the last three years (as opposed to the few years before that), few newbies, especially few idol groups, have gotten into the top ten. My impression is that this is fairly recent in the U.S., that acts are breaking in to such an extent. And again, this is an impression that I haven't checked out.

In Korea no foreigners get near the top of the singles chart, though a track by Maroon 5 or Carly Rae Jepsen may scrape into the Top 40 and then hang around forever in the lower reaches.

*Which is suppressed anyway, I believe; I intend to do a post one of these days about that.