What came through the airwaves 40 years ago, you have to dig for now.
Good stuff is out there, you just have to work to find it.
Does that include new Indie songs? I think they would have a different approach to music since they're not mainstream. They also don't prioritize their music to get sold, which comes to the thought that they'd be more original and free from conforming to the audience's demand.
One could argue that new music by John Mellencamp is indie music because it fits the criteria of the definition you posted. It isn't mainstream because mainstream stations don't pick it up, he doesn't care if a lot gets sold and he creates what comes to him naturally. It's a hobby for him at this point in his career.
The definition of indie music centers on the music and its relation to the industry, not the person creating it or their status in the industry.