Why has transportation progressed so slowly, relative to expectations?

It will be the age of press-button transportation. Rocket belts will increase a man's stride to 30 feet, and bus-type helicopters will travel along crowded air skyways. There will be moving plastic-covered pavements, individual hoppicopters, and 200 m.p.h. monorail trains operating in all large cities.

The family car will be soundless, vibrationless and self-propelled thermostatically. The engine will be smaller than a typewriter. Ccars will travel overland on an 18 inch air cushion.

Railways will have one central dispatcher, who will control a whole nation's traffic. Jet trains will be guided by electronic brains.

In commercial transportation, there will be travel at 1000 m.p.h. at a penny a mile. Hypersonic passenger planes, using solid fuels, will reach any part of the world in an hour.

By the year 2020, five per cent of the world's population will have emigrated into space. Many will have visited the moon and beyond.

Those not atypical forecasts are from 1961, courtesy of www.geekpress.com.  But the rest of the predictions are eminently sensible, if not always accurate.  Or try watching The Jetsons.  Why have we expected so much more progress in transportation than we have received?  I can see several hypotheses: 

1. In the last fifty years, for technological reasons, transportation has been relatively stagnant.  More decentralized uses of flying still consume too much energy and are too dangerous.

2. The public nature of the relevant property rights (e.g., roads, airspaces) has hindered progress.

3. Futurists have no job or no audience unless they predict changes.  They are especially inclined to exaggerate about transportation, perhaps because it is so visible in our lives.

4. We have focused on moving physical resources and information, rather than moving people.  In the former areas progress has been immense.  Who needs better transportation when the world can be brought to your doorstep?

Addendum: David Hecht sends me another reason:

"What Bill Buckley once called the "hysteresis effect". When he was traveling around the world on the Concorde, some years back, he observed that--although long-haul transportation as such had gotten much faster in his lifetime--the total amount of time actually needed to get from point A to point B had not diminished proportionately, because of the increasing amount of distance (and therefore time) between the point of departure and the point of embarcation: that whereas when trains were the done thing, it took maybe 10-20 minutes to get from your front door to the station; with prop aircraft and downtown airports, maybe 30-40 minutes; with jet aircraft and "modern" air terminals, an hour or two; and that--speculatively--if there were ever hypersonic transports capable of going from Los Angeles to Tokyo in 45 minutes, it would take three to four hours at each end to travel to and from the spaceport..."