In its 12th week atop the Billboard Hot 100 chart, “Old Town Road” has become as vaporous as the faint din of car honks emanating from the street outside a closed window — it’s there, but not really there. A hazy memory of a sugar-rush headache. The song you’ll sing at karaoke, or your kid’s birthday party, or your high school reunion, to remind everyone how silly and carefree you once were.

Its reign — first as a SoundCloud loosie that turned into a viral meme hit, later as a simpatico duet with Billy Ray Cyrus — has been mighty, and also meaningful. New songs by Taylor Swift, Billie Eilish, Post Malone, Shawn Mendes and Justin Bieber have had to settle for second. And “Old Town Road,” a casual hip-hop production shrink-wrapped in a pastiche of Western-themed catchphrases and sounds, forced some kind of reckoning — maybe lip service, maybe deeper — in and around the country music business about just what its boundaries are, and why.

An auspicious start to a career, no? The 20-year-old Lil Nas X split the difference between prankster and proselytizer and — for a moment, at least — seemed equally good at both.