I don't think marketing is the decisive measure; sometimes it helps, sometimes it doesn't, sometimes it's unnecessary. As a famous example I mention Billie Eilish; I read that they uploaded their first famous song only on Soundcloud so that a friend could hear it; so not exactly an (intended) marketing measure; but as luck would have it, thousands then suddenly discovered and heard the song. The rest is history. But I know far more at least equally talented musicians who upload songs to Soundcloud without anyone taking notice.
Unfortunately beeing "good" and "original" is not enough; and even if you make it as a musician, it doesn't mean that you can make a reasonable living from it (which is also addressed by the article).
As well as timing and luck.