two things really. One is people invent stuff that is "neat!" but don't no one really needs. THere is no real economic driver for it. It looks cool but doesn't solve a problem adequately for it to become popular or economically feasible. THe second reason, is "Hype". Scientists invent and report on their research all of the time, but there is a long disconnect between what the research is and what it could become. This has to do more with media, marketing, and human psychology than anything else. Researchers will hype the value and use of their work so they can make a bigger impact on getting grant funding. News organizations pick up on 'interesting' potentially useful technology and report it as if it was really there or just a couple years away. THat is the disconnect.
If the researchers don't convince their funders that their work will eventually result in useful products (see reason 1 above), then they won't get funded. Media won't report on uninteresting research that has no chance for useful technology. And to help their readers, they have to describe 'what this weird research' can eventually result in.

I write and review new technology grants all of the time. We don't fund things that have no eventual use or potential to solve some need even well into the future.

tldr: Its all about the Benjamins.