Think consumer level, mass adoption of email in the beginning. People didn't get it (and the very expensive hardware, difficult new knowledge, etc) to communicate - none of their friends had email yet. They did it for status and self image. The cost and difficulty of the task were part of the benefit at that time.
New tech must meet some emotional level desire - even B2B stuff. Someone needs to take a risk to adopt it first - there needs to be sufficient payoff - emotionally - for that to happen.
Superior tech, by itself, rarely is enough to make new tech "promising".
My unsuccessful guess: technologies that are currently serving a niche well but aren’t yet modified to serve the masses.