The Evolution of English

BBC Radio 4 - Today, 20/07/2015, 'It’s definitely not laziness!':

On "the distinctive Scottish rolling "R" being lost as younger Scots no longer pronounce the letter as forcefully":

Host: Is there anything we could or should do about it?

Eleanor Lawson, sociolinguist at Queen Margaret University: I don't think there's anything we should do about it.

Language changes all the time.

In Anglo-English, R began to disappear from about 1700 and originally it was a working class London feature and it was heavily stigmatized.

And today most Anglo-English speakers don't produce R at the end of words and it's completely acceptable.