"Rapidly growing cities benefit from scale economics. As a city grows, it spreads the fixed costs of providing services across more units, thus lowering unit costs and enabling taxes to stay low," explains Renn. "The real question is what happens when the growth cycle ends and unit costs either flatline or start going up. Can the city find sustainability demographically, economically and fiscally without growth as a fuel?"
"This is the mark of a great city," he continues. "A London or a New York can sustain and reinvent itself across growth cycles. Too many places, particularly our Rust Belt cities, have not met this challenge. When the economy shifted and growth ended, they went into a decline that has not yet abated."
"Rather than making today's Sun Belt boomtowns smug, this should serve as a cautionary tale. Even the most prosperous and seemingly invincible cities can be undone when trends shift and growth fades."