It isn't really because introducing the "flying car" would result in a complete rework of cities, roads, safety and not to mention the new training involved. Everyone would need to train to be a pilot of sorts.
Cars worked right away because they fitted into cities and towns, fowards backwards, left and right. If you brought in "up and down" then it changes a lot. People can barely drive as it is, so flying at whatever speed and at whatever altitude would be a death trap.
Until the right propulsion, right safety measures, right training, easy to use mechanically so that Chav McChav and granny and grandad can use it, the right design of a city that would allow it to even happen, then
maybe its doable.