Music is a thing people do because they love.
The vast majority of people who do music, pay money to do it. They spend money on instruments, on lessons, on rehearsal space or a spare bedroom to practice... it's a passion project, like owning a horse, or racing motorcycles.
Now, time for a quick vocabulary break...
In the recording/music industry, "artist" is the term for people whose name goes on the record, not "musician".
"Musician" is the term for people who get paid by the hour or by the session to play the notes on the paper. Session musicians, studio musicians, etc. The guy or gal who played cello for Nirvana was a "musician". Kurt Cobain was an "artist", in music-industry speak.
If you really want to pursue a career as an "artist", it's a terrible idea, it will probably take over your life, you will probably fail and end up living in a van down by the river, but some people still do it, thank God, and for every thousand homeless failures, there is one person who brightens the day of millions of people on the radio every day.
If you want to be a "musician", then it is a viable, if difficult, uncertain, and relatively low-paid career path. You really want to work on your sight-reading ability, and also your sonic/stylistic versatility.
If you can show up and play the part perfectly off the page or by ear the first time (ideally both), and if you understand the gear and sonics sufficient to deliver the right stylistic sound every time, then you can absolutely make a living as a musician.
Maybe you're playing a wedding this weekend, and then a radio jingle on Tuesday, and hoping for a studio session next week, and in talks with a tour-manager about the possibility of playing backup trumpet (or whatever) on a 3-month tour in spring, but if you are good enough and reliable enough, you can find work.
Things like retirement savings, health insurance, etc can be difficult, compared with people who have a stable and predictable salary and career-path. But if you are very, very good, and willing to show up anywhere, anytime, to play music on demand, it's definitely possible to make a living wage as a musician, if you are willing to throw all your time into it.