No it does not mean things are set in stone. Personal jet pack is here albeit still in its infancy. I'm quite sure people are researching into ways to make car

No it does not mean things are set in stone. Personal jet pack is here albeit still in its infancy. I'm quite sure people are researching into ways to make car flies. I don't think you can have time-travel (hence no faster-than-light-travel either). Of course there are "impossible" Hollywood tricks and of course some of the things would take longer to be created. Sometime people invent something for a specific goal but ended up as something else. Nobody plans to create post-apocalyptic world. But if the invention evolves or ended up as a base to create something else, who knows what it'll turn out to be? Take plastic as an example of that. Yes, I do aware of the other things to be afraid of.