Where’s the flying cars?
I don’t think you want flying cars.
More precisely, you don’t want anyone else having flying cars.
I’ve noticed there are a lot of futurist predictions which we’ve reached the time & technology for, but then realized “no, we really don’t want that - and whatever problems come with it - after all.” Flying cars mean idiots “driving” in literally all directions, and accidents/malfunctions are more likely terminal; the energy required is far beyond that of 2D driving. Space travel is largely very expensive just to make very long trips to very boring destinations (kudos to SpaceX’s plans, but those arriving on Mars will find stark raging blah). Eradicating all pests would devastate ecosystems. Instant food is kinda gross. Etc...