Enough old factories and warehouses in downtown St. Louis have been redone as apartments and condos that the area is ripe for construction of new housing for millennials and empty nesters who prefer the city center, Lewis said.

He added that tech firms and other companies needing less office space will continue to prefer downtown St. Louis. Clayton will remain attractive to bigger companies in part because “it is a little cleaner and executive-staff oriented,” he said.

Megadowntown’s parts will continue to define themselves, said Lewis, adding that downtown St. Louis stopped being a retail hub long before Macy’s closed in 2013.

“I can’t even buy a shirt downtown,” he said. “I have to go out to the western part of megadowntown to do that.”

Bolstering the idea of a regional urban core are records showing that most construction in St. Louis is within its part of megadowntown. Permits issued for projects in the six wards partly or entirely within the central corridor accounted for more than $780 million of the $1 billion in building and trades permits issued in the fiscal year ended June 30. (Trades permits are for electrical, mechanical or plumbing work.)