"Publishing companies" are the business half of songs. If you are trying to get songs recorded by artists, or have songs in the marketplace, publishing is the conduit you have to have to make connections. You are by definition self published, as publishing is half a song.
But if you are not connected to record labels, artists, or in the circles the industry runs in, you have no ACCESS to the industry. They also have the machine in place to collect money on your song if any is earned.

Until you are somewhat known and have activity, writing songs with established artists, writing in writer's circles, songs that are being recorded, in film, television, motion pictures, etc. you are not going to be allowed into their circles. It is not something you can just join. You have to be invited and they don't accept unsolicited material or artists.

Publishing is another step along the journey, but one that comes later in the game.

The majors of course are going to be better than the rest because they have the political and financial machine to get songs and writers where they need to go. You know most of the names. SONY, WARNERS, EMI, UNIVERSAL, there are really only about four majors left. They are multi-billion dollar conglomerates, that are affiliated with record labels, movie companies, television, etc.

There are also "Co-publishing" ventures,where a smaller company pairs up with the large one. Taylor Swift, for instance has her company "BIG MACHINE" paired with SONY. She is the largest publishing and record entity in Nashville and one of the biggest in the world.

All of this are things about the MUSIC BUSINESS. Just like the article states "music is lousy". The proof in that is lack of sales. People don't respond positively to most music. Music is a very disposable commodity and many companies treat it that way. It takes a lot of money to establish and continue a career. And the audience has to embrace it.

A lot of things involved.

MAB