AT&T promoted the Picturephone as the telephone of the future, but high cost, inconvenience and a lack of compatible devices turned it into the phone of dreams instead. The same fate awaited many more videoconferencing technologies over the following decades, as systems sprouted up in boardrooms and some offices but mostly were reserved for scheduled meetings and for high-level executives.

In the past few years, the cost and convenience of video calling have made big advances. Smartphones, tablets and PCs fulfill the promise of the Picturephone with widely available hardware and software, while in higher price brackets, the experience is more immersive than ever. But even though making phone calls with video is now nearly as practical as doing so without, it's unlikely that the purported phone of the future will ever be the everyday phone of the present.

This has been a big year for video calling, with the introduction of Apple's FaceTime for the iPhone and Cisco's UMI TelePresence for home HDTVs. Third-party software and services, such as Skype, have made video calls possible with PCs and cheap webcams for years and are now coming to smartphones as well.

For people who want to see who they're talking to, there are fewer barriers than ever to completing the picture. Yet video calling has yet to achieve the worry-free ease of traditional phone calls or even mobile text messages, analysts say. And even if it did, it's not clear people would want to use the space-age wonder of 1964 for every call.

"The research shows people having serious interest in the whole concept of video telephony, but I don't believe they're ready to make it ... their constant form of communication," said Tim Bajarin, a longtime technology analyst at Creative Strategies.