I have two friends that have done quite well with instrumental music.
One does electric “fusion style” music and he’s toured worldwide and made a good living for 20 some years.
Another does traditional acoustic folk / bluegrass / bottle neck slide instrumental tunes. He does ok. Done a few national tours.
Both have put out a few albums.
Neither would qualify as any kind of ‘star’ but have decently supported themselves only doing music.
Here’s the rub however.
They’ve worked their asses off!!!!!
Building a loyal following, developing a fan base, building relationships, keeping those relationships alive, getting to know club owners, putting in the time on social media...... I could go on and on.
With today’s internet connectivity, more communication avenues are available, but the competition for those ‘airwave’ is more intense also. Easy to get lost in a sea of artists.
Bottom line....... If your willing to work your ass off, yes you can do it.