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?

at least nuclear rockets is making a  comeback.

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

at least nuclear rockets is making a  comeback.
https://www.nasa.gov/press-release/nasa-darpa-will-test-nuclear-engine-for-future-mars-missions