Notwithstanding the successes of 'Bohemian Rhapsody', 'Straight Outta Compton', or even 'Rocketman', musical biopics weren't always the surefire Oscar hits that they've now become.

Once upon a time, musical biopics were less about ensuring an actor got a nomination for wearing the correct wig and learning how to play guitar and more about a true desire to a musician's work celebrated and documented.

The '70s and '80s saw some of the best efforts put to screen, made with conviction and honesty, and done without a thought to awards recognition or the kind of consideration and homogenisation that musician's lives now tend to get. 'Bound For Glory', focusing on Woody Guthrie's career, 'The Coal Miner's Daughter', 'Sid and Nancy', 'The Buddy Holly Story', John Carpenter's 'Elvis' and the likes of 'Amadeus' had neither the inclination nor the desire to be seen as savvy award-friendly fare.

'Amadeus', for example, ran for three hours, featured then-unknowns like F. Murray Abraham and Tom Hucle, was laden with stuffy classical music and operas, yet what made it so powerful and so compelling? When you come right down to it, 'Amadeus' was a psychological war movie between Salieri and Mozart, with the two men battling across time and music to outdo one another. The music, gloriously staged as it was, merely provided the weapons for them to do battle with one another. Salieri was fighting God, Mozart was fighting his own worst impulses.

'Sid and Nancy', meanwhile, made a point of making itself loud, angry, and violent, and left no taboo untouched in describing just how destructive the relationship was between Sid Vicious of the Sex Pistols and Nancy Spungen. If anything, it dared the audience to find something redeemable in them as they beat and tortured one another in their drug use and their abusiveness. Would a musical biopic that approached that kind of hostility make it through the studio system today? Not a chance.

'The Coal Miner's Daughter' took in the overnight success of Loretta Lynn's life, zooming from the coalfields of Kentucky to the blinding lights of stardom, and while it may now feel like it's somewhat rote, it was done with a level of honesty and consideration for telling the truth that feels empty and hollow in current musical biopics. Sure, the beats are the same - drug issues, family breakdown, learning to funnel that angst into music - but in 'The Coal Miner's Daughter', there's an integrity to it that's unmistakable. It really was like that for Loretta Lynn, and Sissy Spacek's performance just sells it more than a perfect wig or vocal training can do.

Compare this to something like 'Bohemian Rhapsody'. Sure, everybody loves Queen and nobody can deny that Rami Malek gave of himself fully in the role of Freddie Mercury. It attempted to grasp at how songs like 'Another One Bites The Dust' came into being, while balancing that with Mercury's life and loves. But did they really need a whole scene showing how 'We Will Rock You' came into being? Moreover, was it really necessary to have a joke about 'I'm In Love With My Car' and ignore, say, the fact that they broke the apartheid embargo in 1984?

It's not that 'Bohemian Rhapsody' had to grapple with Queen's inability to separate money from success, or even try to rehabilitate some of their decisions, but the fact that it so flagrantly avoided the murkier parts of their story which could have yielded some actual drama and tension. 'Rocketman', a far better movie than 'Bohemian Rhapsody', made no attempts to flatten any of Elton John's violent outbursts, his drug usage, his vanity and ego. If anything, director Dexter Fletcher fused it together with a ripping rendition of 'Pinball Wizard'.

'Straight Outta Compton', a commercial success undoubtedly, utilised the tried-and-tested rags to riches story of how NWA went from Compton to Hollywood. It worked, yet the allegations of Dr. Dre's abuse never once made it into the movie, nor did the incident with Dee Barnes, which was cut from the script, according to a report in the LA Times.

The musical biopic has gone from being a way to interrogate an artist's work and career to a way of revising and rewriting their story. That Madonna is now writing and directing her own musical biopic shouldn't come as any shock. If anything, it represents where musical biopics are now, and how far they've come from. There can't be any kind of reality when the subject matter is this close to it. How could there be?

'Stardust', the upcoming biopic about the early years of David Bowie as Ziggy Stardust, has no support from the Bowie estate - yet there it stands, vaguely reminiscent of '30 Rock' and the ill-fated Janis Joplin biopic that starred Jenna Maroney as Jackie Jormp-Jomp / Janette Jopler / Janey Jimplin.

The line between veneration and examination in musical biopics isn't always clear. It's hard to pinpoint the exact turning point from when musical biopics left behind any kind of honesty and went full-blown into fantasy rewrites. 'Ring of Fire' and 'Ray' both had in them a similar framework, surgically accurate to Oscar voting sentiments. That's not to say for a second that Jamie Foxx, Reese Witherspoon, and Joaquin Phoenix didn't give it their all or come to the roles with anything cynical, but the truth is that their performances were all heavy favourites for awards season gold and won out in the end.

It's not been all buzzy, Oscar-bait dramas in the field of musical biopics of late, however.

Anton Corbijn's 'Control', focusing on the life of Joy Division frontman Ian Curtis, was starkly real and made no attempt to cushion his relationship with his wife, played fantastically by Samantha Morton. Sam Riley embodied the rage and the savagery in Ian Curtis, and the black-and-white photography heightened the tone and the gloom of Joy Division's sound.

Steven Soderbergh's 'Behind The Candelabra' was a gloriously camp, bitterly funny examination of Liberace's life and loves, but did it without any cloying sentimentality. Michael Douglas' performance was witty and knowing, and walked the fine line between the seediness and neediness in Liberace's private escapades.

Yet, for these examples, musical biopics now are synonymous with by-the-numbers, run-of-the-mill Oscar-bait because that's what does business nowadays. Yet, if there is to be any kind of integrity or any real attempt to examine the lives of musicians, there has to be some baseline attempt at being truthful, and not simply papering over the moments they don't want people to see, or would rather skip over in favour of the greatest hits.