Many inventions were deemed toys and future failures of no interest.
Telephone, internet, automobile.

In 1939 the New York Times stressed that "TV will never be a serious
competitor for radio because people must sit and keep their eyes glued
on a screen; the average American family hasn't time for it.” Meanwhile,
20th Century Fox boss Darryl Zanuck claimed in 1946 that “TV won't be
able to hold on to any market it captures after the first six months.
People will soon get tired of staring at a plywood box every night." And
in 1948 BBC radio exec Mary Somerville called the technology “a flash in
the pan

Internet
©Courtesy Newsweek
Back in the mid-1990s a number of experts were less than keen on the
internet, which they viewed as a nerdy fad that would end up going
nowhere. By way of example, a now-infamous article penned by scientist
Clifford Stoll in 1995 for Newsweek entitled "The Internet? Bah!"
slammed the innovation and predicted it would crash and burn.

Also in 1995, Ethernet inventor Bob Metcalfe (pictured) wrote in an
opinion piece for InfoWorld magazine that “the internet will soon go
spectacularly supernova and in 1996 catastrophically collapse”. Metcalfe
vowed to eat his words if he was wrong, and did just that at the World
Wide Web Conference in 1997 when he blended a copy of the article with
some water and drank the concoction.