1940's - movie studios had to divest their distribution channel - they owned over 50% of the movie theaters in the U.S. "It's all over," complained the studios. In fact, the number of screens went from 17,000 in 1948 to 38,000 today.
1950's - broadcast television was free; the threat was cable television. Studios argued that their free TV content couldn't compete with paid.
1970's - Video Cassette Recorders (VCR's) were going to be the end of the movie business. The movie businesses and its lobbying arm MPAA fought it with "end of the world" hyperbole. The reality? After the VCR was introduced, studio revenues took off like a rocket. With a new channel of distribution, home movie rentals surpassed movie theater tickets.
2000 - Digital Video Recorders (DVR) like TiVo allowing consumer to skip commercials was going to be the end of the TV business. DVR's reignite interest in TV.