Cable television. Without a cheap and expansive media to move it, it is hard for something to become mainstream. But, there were paintings and Victorian decorations long before the 60’s. Just now, the internet, dvds, and pay per view tv makes it easier to distribute.
Cable is very recent, your left wing gains started well before cable, think the 1960s, the Warren Court, Rove V Wade, the feminist movement, Hollywood, the ACLU the growth of the entire anti-American, anti-Christian movement.
You guys have had great success in the last 60 years or so.