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.
Cable television has been regulated by the government since 1949. It became huge in the early 70’s. TBS started in 1976.