Question about IM/Twitter short-cut spellings [View all]

The current thought about the change to a more phonetic or tortured acronym conveyance of a message - e.g.: "c u soon" or "ttyl" is that people use it as a short cut because they hate to type on their phones.

But why haven't we fallen into this before? Far fewer people before knew how to type than they do now. And with telegrams, brevity saved money.

I see how it evolved to this, but why did it need so darn long?