Every city has a sex and an age which have nothing to do with demography.
Rome is feminine. So is Odessa. London is a teenager, an urchin, and, in this, hasn't changed since the time of Dickens. Paris, I believe, is a man in his twenties in love with an older woman.
Demography is changing us as we are older societies, we're living longer.
How the generations balance each other out, how that affects education and health care.
When a record company looks at me I'm very hard to market, I don't really fit anywhere, It's hard to get me on the air, and I'm hard to demography, but! because of that I'm not subject to trends like you pointed out.