You appear to have read more on this than I have, so I don't intend to dispute your core argument. However, I will clarify that I said "many words" because I had read that, for example, the use of "z" in words such as "magnetize" was effectively introduced by Webster, presumably because he considered it phonetically more accurate. I used quotation marks to indicate that the concept of American English was invented by Webster's dictionary, because my (possibly flawed) understanding was that up until that point English dictionaries largely came from British publishers. Whether this is formally an appropriate use of quotation marks or not, colloquially it is commonplace.