Everything starts underground at first. How do you think we get it in the first place. All forms of art
Examples.
Rock - comes from Folk, Blues, and Jazz which all developed through the 1800s to the early 1900s. I mean you can go as far back as the guy sitting on the front porch strumming on his old banjo with civil war canon balls landing in his front yard.
Movies - still photography, primitive crank-motion cameras
Artwork - cavepaintings
You see nothing, is mainstream until it has at one time been underground. Everything has to develop and until it has, it is underground, but once it does, it becomes mainstream once it is made available to the masses.
