In modern times, it's almost unheard of for a city to run out of steam, to disappear or to become obsolete. It happens to companies all the time. They go out of business, fail, merge, get bought and disappear.
What's the difference?
It's about control and the fringes.
Corporations have CEOs, investors and a disdain for failure. Because they fear failure, they legislate behavior that they believe will avoid it.
Cities, on the other hand, don't regulate what their citizens do all day (they might prohibit certain activities, but generally, market economies permit their citizens to fail all they like).
This failure at the fringes, this deviant behavior, almost always leads to failure. Except when it doesn't.
Ecosystems outlast organisms.