It was certainly always hard to become a megastar, but it used to be a lot easier to put out a genre record (eg techno, drum'n'bass, jazz) because a well-run label had a pretty good sense of what would sell enough copies to turn a modest profit for everyone involved. An album that sold 4 or 5000 copies to a niche audience could make about 25k each for the artist and the label (record deals in genre music are generally a more equitable than major label ones). That's not a lot, but it's not terrible either, you could pay your rent with it. Nowadays you'd be lucky to sell 1000 copies, so small labels are correspondingly less willing to take a risk on unknown artists, and there are fewer labels with the expertise in distribution, marketing, and developing an artist's career than there used to be.
If an artist is good, they will probably get viral
Don't be absurd. Justin Bieber is talented, but he's also extremely attractive and happens to be proficient at the sort of music that appeals to teenage girls. That's a bit like expecting J. Random Developer to enjoy the same sort of success as Bill Gates, and concluding that if he doesn't it must be because he's no good as a programmer.
Well then maybe the way the market is only certain people can get paid that much (just like a random developer becoming the next Bill Gates). Also I said artist not musician, Bieber got to where he's at not for being a talented musician but for being an artist (attractive, catchy, etc).
If an artist is good, they will probably get viral
Don't be absurd. Justin Bieber is talented, but he's also extremely attractive and happens to be proficient at the sort of music that appeals to teenage girls. That's a bit like expecting J. Random Developer to enjoy the same sort of success as Bill Gates, and concluding that if he doesn't it must be because he's no good as a programmer.