> Not convinced of the point that these inventions "come from science fiction", sci-fi popularizes and speculates about the future of current science and technology, it doesn't invent the science and technology. Cell phones have existed in experimental forms since the 1940s[0] so they certainly weren't invented by Gene Roddenberry, he just speculated that they would become smaller and more powerful.
To amplify your point: it's worth noting that the Star Trek communicator was depicted as a compact, extremely long range two-way radio. Cell phones only vaguely resemble them. So even less credit is due to sci-fi.
I think it's also the case that multiple concepts end up manifesting in ways that we can't envision or simply don't consider (see Marshall McLuhan). For example, this was also science fiction, but is probably much more relevant than a two-way radio when considering how we use our mobile devices, even if the form factor is far closer to a tricorder: https://en.wikipedia.org/wiki/Memex
To amplify your point: it's worth noting that the Star Trek communicator was depicted as a compact, extremely long range two-way radio. Cell phones only vaguely resemble them. So even less credit is due to sci-fi.