Well, to understand the future, we need to focus on the past.
Some people may say it was because of the religious conflicts (the church was on charge) in the Middle Age that made a scientific oppression, resulting in a world with limited freedom, and then, we got a little "late" comparing to our main goal. Although, this is one of the possible answers, and I'm NOT making fun of other people's religious (if they have one) beliefs, just to clarify.
Though, if you want a more "recent" answer, I could say that what people were used to say in the 90s or in those years were just speculations, in the same way we're still going to think that these same things are going to happen in 2020, or even maybe in the very next century.
Now I'd like to talk about the flying cars, food pills etc.
When you mention a "flying car" it will not be a car, technically... it will become an airplane. Because airplanes fly, obviously... but about the "flying cars", they have been tested, but without organization, this idea would become a large scale disaster!; Now about the food pills... as far as I know, astronauts have already taken them; scientists are developing robots to do simple tasks; virtual reality (google glass or oculus rift) became very popular, as well as holograms (Michael Jackson hologram was made during a musical event) have been developed; space exploration is something that happens a lot (or at least people say it does), and NASA spends a lot in these types of projects. All these things are in a progress. Slow for someones, fast for others.
Then... the things we didn't make yet: jet packs, moon cities etc. Probably they weren't made to avoid confusion (like people's reaction to the first computer, telephone etc.), but somebody needs to try at least to know the results! About the moon cities, I am not even sure if humans have really gone to the moon, because if they did this about 45 years ago (I don't know if I'm right about the time), why couldn't they develop really advanced metropolises and resources there? Unless if it was all a lie and they have never went to the moon.
People are not ready for the future. We cannot even deal with the past! The society will do amazing things, but it's only possible if they try to do it.
