Extensive use of abbreviations and acronyms was primarily a convenience for writers, when writing was done by hand and then by typewriter, there is less justification for it now when most writing is done by computer.

I don't agree. My impression is that the popularity of abbreviations and acronyms is being driven by the rise in popularity of text messaging, which is usually done from phones with tiny, unusable keyboards; instant messaging, which is done in real time; and social networking site based communication, which often has hard limits on message length (e.g. Twitter).