Adele?

Nearest example I can think of, mySpace was where she got noticed so that dates her breakthrough to a good decade ago.

Adele was legitimate however others have pretended to have an Adele grade story. Lily Allen also claimed to have been discovered on mySpace but her dad was rock and roll celebrity so her efforts can be dismissed as nepotism. Often these links to rock and roll celebrity are not obvious because performers use stage names that sound like real names. Their children don't use their parents fake surnames.

Adele wasn't self-published though, right? I'm not super familiar, but based on the wikipedia page she got picked up by an XL Recordings talent scout who put her on other albums associated with that label, including appearances on BBC, before even her first album, which had 32 credits.

Being really good and self publishing helps you build your resume in a superstar industry, but it's nearly impossible to actually achieve commercial success without a well-established sponsor. Adele probably wouldn't have gotten far on her own if XL or some other label hadn't picked her up. Her accomplishment before then was a really good resume.

Her mySpace tunes were self published, however, getting XL Recordings on board has parallels with startup culture. It is like the importance of having a co-founder, proof that you have convinced someone to back you, then with that, you can scale things up.

XL Recordings came from the rave scene, the Prodigy were their first big earning group, however, for every Prodigy there were scores of 'Dome Patrol' grade releases that nobody except for DJs ever heard of. XL moved on when the rave scene died to other acts in different genres. They 'pivoted' to use the parlance.

I know Adele worked with a label however it was a genuine thing her getting spotted on mySpace and not some fake back story, as per the Lily Allen example. I don't believe music executives really would listen if I posted my singing efforts to the internets, or if anyone here did likewise. Yet that did happen with Adele.

I'm not saying that Adele's story isn't remarkable or that she isn't talented, but that she didn't break the industry pattern, finding her own slice of the pie without help. XL already had audiences, resources, collaborators, and connections, and a production pipeline that she was inducted into. Her debut product took 32 people to make, on XL's dime. It was not a Stardew-Valley situation.

Justin Bieber was discovered through YouTube. And he helped contribute to Carly Ray Jepsen's career because he saw one of her songs on YouTube, covered it, and helped it go viral. The Weeknd used YouTube at the start of his career as well.

I don't think this phenomenon is limited to one form of media. "The Martian" by Andy Weir was originally published on his website one chapter at a time. The internet has, in general, lowered the bar to publishing any kind of work significantly - be it games on Steam, songs on YouTube, or ebooks on Amazon. There are now new avenues into the wider industry, but the big players are still the big players.

People break through all the time. But there's no formula for it. It's luck + talent + zeitgeist + social connection. You don't need all 3, but it helps a whole lot. And you can have a whole lot of any of them and still not have lasting success. This is how the music industry has been for a long time, although the dynamics are always, well, dynamic.