"Dear" as in "expensive" is in everyday use in Scotland, and probably the rest of UK.
An interesting point about this discussion is that it is an example of the contrasting roles of speech and writing in transmission of communication.
Writing (and print) evolved for communciation over distance, whether the distance is geographical, or across time ( I was going to say "temporal" but I suspect that means something else) Speech is immediate and ephemeral.
In previous centuries, words changed, meanings evolved and no-one noticed, or at least not many people recorded the occurrence if they did notice. What's different nowadays is that the pace of change has been accelerated by the adoption of speech as a medium of communication over vast distances via TV, radio, film etc...
Also, increasing literacy has meant that change to the written language has been dragged along in that process too..
Where changes in word meaning occurred in past centuries, say in the lyrics of a song, I'm sure that people either changed to a different word to retaiin the meaning, or else stopped singing the song, or dropped a verse, or made up a new line when they couldn't understand the sense of the old one.
I understand the point, and I personally regret the loss of some meanings when a new one "takes over", but it's a living language, and when it doesn't have the capacity to change and grow, it'll start to die...