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 ☀️

rss feeds not potent enough and couldnt overcome the externalities of centralized feeds

they're still kinda there as a backend plumbing technology even though they didn't make it as a consumer media technology