It is in line with stats I read recently:

70 % of all published songs/albums sells 1 (hello mom) or none.
90 % sells less than 100
1 % sell enough for the artist to have a decent income from her/his music.

Of the 10% selling more than 100 albums: 8 out of 10 are backed by extensive marketing from a label.

There is however other ways to get income from your music. I have several friends who submit tracks that they don't want to publish in their own name to places like Pond5, etc. - and they actually get a decent return of money from those "abandoned" tracks.

Also... you will probably get some confidence by listening to new songs in your preferred genre... there are so many really bad written/produced songs that would NEVER have been published 10-20 years ago (before you could do everything yourself).

Will