Most people who have gotten big on the streaming platforms will talk about endless grind - I believe a depth of content sets up a virtuous cycle on platforms like YouTube. Yes you might have an Uncle Roger moment where you go viral and get that massive step up but many other streamers will talk of putting out years of content before getting traction.

Not sure how it works specifically with music because you can't really churn out endless original content. I guess part of the churn can be covers or live performances.

Connections do help tho - getting someone to promote you on their channel always helps but I'm told the online content community are actually extremely supportive and friendly.