After WWII FM radio arrived with the prediction that AM radio would be
dead in five years due to the better sound quality of FM.
For years in the 60's and 70's movie theaters ran trailers to "Fight
Pay TV" (cable) claiming it would put movie theaters out of business.
Today film companies gross more money from videotape sales and cable
rights than box office sales. Within 8 miles of my home there are four
theaters with 32 screens.
The audio cassette was introduced in 1967 and is still with us. Eight
tracks (remember eight tracks) were still a tape medium but lacked the
versitilty of audio cassette. After 60 years Vinyl was driven out by
Audio CD-ROM in 30 months - but audio cassettes roll on. Hmmmmmmmm.
The axiom is: "The introduction of a new technology does not
automatically drive out an old technology."