It’s 2015, and the kids are taking over. Exhibit one: Unlocking the Truth, three adorable African-American youngsters from Brooklyn aged between 12 and 13 who got their education headbanging to Metallica and Disturbed, and last year signed a five-album deal with Sony. Exhibit two: Residual Kid, three 14-to-16-year-olds from Austin, Texas who make like a minipops Nirvana and in November inked a deal with Sire Records. Neither are reinventing music, though both are accomplished enough to make you think back to whatever the hell you were doing at that age and feel very ashamed.

But here’s the thing: both bands are almost certainly screwed. Unlocking the Truth signed to Sony for a cool $1.8m, meaning they need to sell a quarter of a million albums to cover their advance – a tough call when riff-led metal isn’t exactly setting the charts alight. Sony, of course, intends to cash out: it’s a 360 deal, meaning the label gets a fat slice of touring and merch receipts. But the long-term prognosis for child stars is seldom good. Barring a miracle, Unlocking the Truth will have passed through the music industry’s digestive tract by the time they’re old enough to… well, do any of those things that rock stars like to do.

For major labels, youth equals novelty – hence why there’s more talk about a planned Unlocking the Truth documentary than their actual music. And nothing is more disposable than novelty.

Thankfully, in this age of self-publishing and YouTube tutorials, we’re witnessing a generation of youthful music-makers succeeding on their own terms. Lewisham rapper Novelist has been at it since 2011, cutting his teeth as resident MC at London grime hothouse Boxed, scoring a MOBO nomination last year for best grime act and popping up on the BBC Sound Of 2015 longlist – not bad, given that his debut EP for XL Recordings, 1 Sec, lands this week on his 18th birthday.

Then there’s Catalonia’s Mourn, who release their self-titled debut on Captured Tracks next month. Grittily romantic indie-rock with shades of PJ Harvey, the music in no way indicates that the band members are all aged 15 to 19. More unexpected still is Henry Plotnick, a young San Franciscan who started copying Philip Glass’s music on his parents’ piano aged seven, and at the ripe old age of 13 is a fully fledged minimalist composer: see his new 70-minute cassette Blue Fourteen, which employs a keyboard and looping software to build a beautifully intricate sound collage.

The examples of Unlocking the Truth and Residual Kid feel like the last gasp of a dying model: ageing record executives throwing silly money at bands they think 15-year-olds will like. If Novelist, Mourn and Henry Plotnick tell us anything, it’s that it’s best to leave the kids to their own devices.

1 Sec by Novelist x Mumdance is out Tue