Is The Voice ‘building careers’ and not ‘flash in the pans’?
It's not a new question, but it is one to which the BBC's prime time Saturday night offering The Voice has long been subjected: When is the show going to produce a superstar?
Its TV rival The X Factor can silence any critics by simply whispering the words One Direction.
The Voice happily shouts about Becky Hill, a semi-finalist from series one who had a number one with Oliver Heldens on the track Gecko (Overdrive).
But Hill is not quite in the same league as 1D - yet.
"It (The Voice) might not be churning out superstars to bridge the gap until the next series," explains one of the show's coaches, Ricky Wilson, "but I think that's a good thing.
"We're building careers, I think," he goes on, "we're not building flash in the pans" before hastily adding "that's not at the detriment of anyone else by the way".
Jermain Jackman, 19, won The Voice in 2014 and while he put out an EP last September, his first full album isn't released until March.
"It's that whole sense of working hard in silence and letting your success make the noise," Jackman explains.
He says he's been surprised at the amount of creative freedom he's been given on his debut, but is he prepared to be criticised if he doesn't get a number one with this first release?
"I don't like that," he admits.
"People can put a lot of pressure on you," Jackman adds, "but I'm not pressured, Amy Winehouse never had a number one but look how successful she was."
Jermain Jackman was mentored on the show by will.i.am and while the pair are still in touch, Jackman doesn't like to bother him too much.
"I'm a friend and a confidante," muses will.i.am about his role as a coach on The Voice.
He then smiles as he breaks into a chorus of the theme to 1980s sitcom The Golden Girls, realising he has echoed its lyrics.
So does will.i.am think it's fair to measure the success of a TV talent show on hit singles it produces from its contestants?
"Whether or not you have a massive hit after the show, shucks," he shrugs.
"As artists we're worried about our hits too! Everybody is worried about a hit."
One issue The Voice has had to confront from the outset, is that despite the show's name and its wholesome intentions, creating successful acts has a lot to do with image and branding as well.
Coach Tom Jones says that has always been the case: "When I first came to London from Cardiff in 1964, they said curly hair doesn't work anymore," he explains, bemused.
"I said, 'Wait a minute you haven't heard me sing yet,' and they said, 'Yeah but the Beatles and the Stones, you know, you're not boyish enough,' even though I was the same age as John Lennon.
"So you're told because you don't look right for the time," Sir Tom concludes, "that you won't make it."
One Delilah and a Green, Green Grass of Home later and the question of his curly hair no doubt had become irrelevant.
Rita Ora is the newcomer to the coaching panel this year, replacing Kylie Minogue, who replaced Jessie J.
It wasn't a decision she took lightly.
"I had to speak to will (i.am) about it first," Ora says "because I didn't know if I wanted to take that pressure on and be responsible".
It means Ora could find herself responsible for mentoring this year's winner, who, with any luck, will be as philosophical about making it in the music industry as Jermain Jackman.
"These things take time and care," Jackman considers, "and I'm grateful to understand that, one step at a time."
The Voice series four starts on BBC1 at 19:00 on 10 January 2015.