So:
Proposition (1) Growth Will be Happening Outside Advanced Economies (nothing new - just check IMF WEO database to see what everyone already knows),
Proposition (2) Cities traditionally power growth (nothing new - just check your history book covering any period since, oh... Mesopotamia).
Take Proposition (1) and Proposition (2), mix up with big brains from McKinsey Institute and you have: (1)+(2)= (3) A Breakthrough Report that Cities of Future Growth will be in... yep, you guessed it right, where that growth will be - NOT in the Advanced Economies.
Who eats this banality? Why, media, of course, who can't put together (1)+(2) to get (3) on their own and thus need McKinsey to do the job for them. I know... it's argument from authority, isn't it?