That's not exactly what I was getting at, but, yes, what you inferred is in fact true. What is the meaning of "acorn"? It's not the same as ACORN or a ton of other acronyms that are also words. And some acronymns, keeping with the examples here, become words and then their case changes along with their assumed meaning. How about LASER? In all caps it suggest the acronymn from which the word laser was derived, rather than simply the word "laser". I would never write that I had a LASER printer. If I read that from somewhere, I'd be wondering what it was that I was suppose to glean from the capitalization besides the type of printer it was.

I also think that it's worth noting that the designers of languages do not seem to be a part of any kind of conspiracy, and given that they are bright, independent people prone to the same conclusions, there must be something of value to the choice of case sensitivity, especially since it also has a cost.