Shenzhen and its people: here to stay?

On the day I arrived in Shenzhen, I had a conversation about the city with a native.  We shared the shuttle bus from the airport to the hotel, and I took the opportunity to ask a stranger a question that had been nagging me.  Almost everyone in Shenzhen is in their twenties, so why doesn't it feel like a college town?

My fellow traveler grew up in Shenzhen before the construction began, but he'd spent the last ten years in Washington DC.  I told him that the last time I was here, I hadn't seen a lot of local culture.  In the US, if you had all these young people living in a citys, there'd be a thriving music scene and sports leagues.  Like Ann Arbor, but fifty times the size.  I told him maybe I don't know where to look, but I haven't seen that in Shenzhen yet.

He said basically the young people are working long hours and sending their money home, so there's no time or money left for cultural activities.  Also, they don't feel like Shenzhen is their home, so they don't want to invest in improving the city itself.  They're not there to stay.  They work for a few years and then go back home to establish themselves.  I found this response both depressing and incomplete.  The kids have got to do something on the weekends.  And at their age, this city must be a roiling cauldron of hormones.  They should be competing to get laid in this pan-Chinese cultural melting pot, inventing and discarding styles faster than the Japanese.  But no.  Karaoke is the closest thing they have to a local pastime.
This time I'm seeing more children and old people here in Shenzhen.  Like the city is here to stay.

That might seem like a staggeringly odd thing to say about a city; the only time a city disappears is when the climate wipes out its civilization, right?  But in 2010 the impression I got was more like a colossal factory than a city, although I couldn't put my finger on it at the time.  A factory can close down if a simple business decision is made.
At a Chinese Walmart, are all the goods made in the USA?
And maybe that's why:  all of Shenzhen felt like a business decision. The Chinese government decided to perform an experiment in openness and modernization.  They set aside a tract of land that for some bizarre reason didn't already have a metropolis on it, and they invited foreign companies to come use their abundant labor.  Everybody won:  the companies got trainable production workers at relatively low wages; the workers got what was for them relatively high wages for a few years.  As time went on, the Chinese government ramped up the value added:  first it was only production workers, then supervisors, then managers, then engineers, then scientists and vice presidents.  At every step, foreign companies got the benefit of low wages, and the Chinese employees got training, and the Chinese government got highly skilled people that could be used elsewhere in the economy - to build Chinese companies, for example.  Really, you have to hand it to them.  It was very well managed for a government program!

But by now, Shenzhen has acquired inertia, a presence of its own.  People actually live here, and not just the people that lived in the sleepy fishing village my fellow traveler grew up in.  The production workers sending money back to their families don't call it home, but others do:  the managers and engineers.  If a factory closes down, those people don't pack up and move back to the provinces, they find another factory.  They're here to stay.  But it's still a mystery to me why those managers and engineers haven't created a local culture.