RE: 10 Ways to Earn Income as a Musician in 2018

(8) Day Job

lol.. after reading the title I was inclined to add day job. But you seem quite realistic about the situation. Others would have added to get a job in the public sector in the area of music like in an orchestra or for example as music teacher who only works 3 hours per week.

Here are some more ideas out of my head:

teaching instruments; ideally to bored housewife with rich husbands:-)
working as conductor for amateur bands as a side job
becoming a music producer in case that's not included in "backing musicians"
organizing music related events/festivals
writing and/or singing pop or folk songs. There are enough extremely good musicians who go the BS road to financial success because it pays much better.
doing something controversial like masturbating on stage while singing (ok, don't do that, but I'm kind of sure it would find its audience)
playing the same song over and over again with a bagpipe as street musician and then getting paid for leaving.
double your price and only work half the time.. in case that works :-)

I will follow you now.