Can less populated cities on the outskirts of larger metropolitan areas be too small to succeed? Are urban municipalities with fewer than 100,000 people vestiges of a bygone era? Should small “inner-ring” cities even exist? These questions are being posed with greater frequency across the country.

“Merger with the central city is an option more physically contiguous inner-ring suburbs should consider,” writes Aaron Renn, a researcher at the Manhattan Institute for Policy Research. Journalist Edua…