It's very possible. IIRC Wells in his book says the main difference in Oz is between rural and urban accents, but that was written 20+ years ago. I do remember that he wrote that some of the "long a" words are "short a" there, probably because they acquired the long sound in English later than the others, after the main Australian settlements were established.
I gather new American accents are evolving too. I'd really only recognise New England (halfway to English English) Southern, and New York/Brooklyn (influenced by immigrants) but apparently there are mid-Western and others. Then there's Canada. To me, Canadians sound more or less American, but to Americans they sound more like English (as do Australians). I think your ear for an accent depends on you how far away it is from your own and ones you hear every day - you'd pick up more differences between yours and a nearby one than you would between two that were both very different anyway.
In south-east England the reverse is happening in that the rural accents are disappearing under the twin onslaughts of a sub-Cockney - because so many Londoners were dispersed to new towns outside the capital - and Received Pronunciation or "posh" because people like to sound educated and this accent is native to this area anyway. By RP I don't mean the upper-class accent of aristocrats, which has been guyed so often it's on the way out, but the pronunciation of newsreaders, some academics and professionals. To my ear a new "student" accent has evolved which is different to this, but then I live in a University town.
Wells does say that accents evolve all the time, quoting Cockney as particularly innovative, though Scouse is another to my ear. Not only is the London speech of Dickens and others long gone, but even that of Shaw in Pygmalion/My Fair Lady is out of date. But then most working-class Londoners don't speak Cockney (east end) but a variant of it, and I believe South London is starting to differ from north of the Thames.
There's endless scope for discussion here.