I'm trying to think of examples of technologies that were innovative and basically worked, but weren't potent enough to overcome the skepticism eventually, and/or couldn't overcome the deadweight of externalities. 

Not potent enough: flying cars
Couldn't overcome externalities: nuclear rockets

Any others?

Blogger at ribbonfarm.com, running summerofprotocols.com, host of /gloom ☀️

gold synthesis using proton bombardment.

A lot of people ignore the fact that today we can literally do alchemy.

WE CAN TURN LEAD INTO GOLD PEOPLE
(at the low low price of a bajillion dollars a gram)