The band announced this week that Brian Johnson is to miss the US leg of its Rock or Bust World Tour after doctors warned he could lose his hearing if he takes the stage.
With the lead guitarist Angus Young the only original member still on stage, Jesse Fink, the author of the bestselling book 'The Youngs - The brothers who built AC/DC', believes it is time for the band to call it a day.
"I do not think that just having one original member on stage really qualifies it as being AC/DC anymore," Mr Fink said.
Johnson's hearing problem aside, the author said the singer was troubled vocally.
"When I saw AC/DC in Sydney I did not think Brian's voice was really up to the task," he said.
"He sounded like he was struggling certainly to hit the high notes.
"And the band seemed to be much more reliant on Angus Young and Angus' solos. And it was very much the Angus Young show."
Replace, disband or continue
The loss of a frontman under any circumstances would raise questions about a band's future.
The editor of Mixdown Magazine, Keats Mulligan, believes AC/DC pulled off a miracle in 1980 when, after the sudden death of iconic frontman Bon Scott, they found a replacement in Johnson.
He's not convinced they can pull it off a second time and thinks it is time for the band to break up.
"I do not think that just having one original member on stage really qualifies it as being AC/DC anymore."
Mr Fink believes Angus Young could and should go it alone.
"He is one of the great performers in rock music," Mr Fink said.
"And, he's got a fantastic amount of energy for a man in his 60s.
"I think he would still fill out stadiums. But you know let us call it something else. Don't call it AC/DC."
Mr Mulligan questions if the band has anything more to add creatively to music.
"That is not to say the sum of its parts do not. I think they definitely do," he said.
The loss of a frontman
In 1980, the English band Joy Division broke up when frontman Ian Curtis died.
Its remaining members formed New Order.
"I think that is a really good example of a group of musicians making a really good decision about how to go forth with a project," Mr Mulligan said.
"Both bands are celebrated and they both have their own successes and they are both understood to be related but different."
After the death of Kurt Cobain, the surviving members of Nirvana went their own ways, with drummer Dave Grohl forming the Foo Fighters.
After four decades with AC/DC, founding member guitarist Malcolm Young left in 2014 after he was diagnosed with dementia.
He was followed shortly after by drummer Phil Rudder who was last year sentenced to home detention in New Zealand after pleading guilty to charges of threatening to kill and possession of drugs.
Much of a band's identity is defined by its frontman and they face the toughest criticism.
"As a fan of AC/DC, I would hate to see them come under that kind of scrutiny," Mulligan said.
"Perhaps we have seen the last tour."
Long-time fan Simon Barber would like to see the band go out on top.
He saw the band's last show at Etihad stadium in Melbourne and says it was not as high energy as usual.
"It was noticeable in December that they took possibly, a 30 second break, between each song", Mr Barber said.
"I'm not sure for the reasoning for that - if it was to allow them to rest. But it did interrupt the flow a bit.
"So perhaps we have seen the last tour."
Filling the void
A yet to be named guest vocalist is to take Johnson's place when the 10 US shows are rescheduled.
Mr Mulligan values the band's working-class Australian background and thinks an Aussie should fill the spot.
"But I would acknowledge that there is no Australian that I think is fit that would resonate with a US audience," Mr Mulligan said.
"My gut is that they are probably going to get someone American to fill the role."
He cites a cover version of AC/DC's 'Let There Be Rock' by the frontman of Australian punk band The Hard Ons and Black Flag frontman, American Henry Rollins.
When loud sound does damage
The band has not released information about the current state of Johnson's hearing.
Loud sounds can damage sensitive structures in the inner ear and cause noise-induced hearing loss.
"It is progressive from day one, as soon as you exceed what is considered to be safe levels," hearing advisor from the advocacy organisation Better Hearing Australia, Sharon Plunkett, said.
In Victoria if you exceed 86 decibels over an eight-hour day you are required to wear hearing protection.
"A rock band is probably over 100 decibels, so their safe time may be five to 10 minutes before they are at risk (of hearing loss)," Ms Plunkett said.
"Musicians have the option of using musician’s plugs that are different from the one's use in industry. They are designed to not distort the music while they are playing.
"But it might not give a musician adequate protection when you are talking about the levels of a rock band."
