My brother recently explained that this picture got so popular because its copyright wasn't renewed, so networks got 100% of the ad revenue. But in 1974, when

My brother recently explained that this picture got so popular because its copyright wasn't renewed, so networks got 100% of the ad revenue. But in 1974, when 28 years had passed, Republic Pictures failed to file a renewal for the film's copyright protection. The film lapsed into the public domain, meaning anyone could show the film without obtaining permission or paying royalties