Much of human communication is conveyed not just through the words that we speak, but also with the tone of voice with which we speak them and our body language as well. It is bad enough that we lose body language over the phone, but the loss of tone with modern largely text-based communications is even more hampering. As particularly poignant example, sarcasm is completely lost in purely textual communications. Certainly, prior to the telephone, long distance communications were also purely textual: but we took more time and greater care choosing our words back then, and I suspect that as such the loss of tone and body language were lessened as such.
Moreover, modern communications has clearly demonstrated that people tend to develop a strange sociopathy of sorts when they communicate online, acting far more passive aggressive and rude than they presumably would be in person. I used to think that was due to the Internet's anonymity, but the advent of sites like Facebook where people act the same under the real identity suggests otherwise.
These are just my observations of the current state of modern textual communications, and the evolution of such innovations as emojis demonstrates an awareness of these phenomena and an active effort to compensate for them and reintroduce an equivalent of tone and body language into texts.
If we had bypassed the ability to transmit audio and video signals, jumping straight from the telegraph to to texting: I imagine that we would been in the same place decades ago as we are now with respect to the limitations of intant text communiques--but my have over time developed better and more clever ways to re-incorporate the equivalent of tone and body language into our textual communications (i.e. starting with emojis and somehow progressing from there). Beyond that, the inability to develop the technology to transmit audio and video signals suggests further technological limitations of greater concern--i.e. no radio, no TV, etc, etc, etc.
