Did the British Invent Their Accent After the American Revolution?

Recently I did a search on Google to determine when America lost its British accent. Much to my surprise, I learned that America didn't lose the accent because neither the U.S. nor the English had an accent at the time!

"Around the turn of the 18th 19th century, not long after the revolution, non-rhotic speech took off in southern England, especially among the upper and upper-middle classes. It was a signifier of class and status. This posh accent was standardized as Received Pronunciation and taught widely by pronunciation tutors to people who wanted to learn to speak fashionably. Because the Received Pronunciation accent was regionally "neutral" and easy to understand, it spread across England and the empire through the armed forces, the civil service and, later, the BBC."

Source: http://mentalfloss.com/article/29761/when-did-americans-lose-their-british-accents

To confirm the theory, I started checking other sites. Although some British naturally disagreed, the proof came when I learned that some rural parts of England still speak in an American-like accent. Since we don't have recordings that old, nothing is conclusive but the diversity of other European lingual influences would still not explain how nearly no trace of the so called "original accent" remains here in the states. Australia it should be noted still retains an accent but the largest influx of English settlers did not arrive there until after the posh accent became predominant.