More nonsense. That infrastructure had existed in small towns for generations and even centuries in same cases, and had been upgraded as needed over those periods of time.
And there is still opportunity in small towns for many. Many small towns still have industries and there are manufacturing jobs, jobs in the skilled trades, and there are doctors, lawyers, school teachers and often hospitals and local government jobs.
I grew up in one that continues to thrive due to a locally grown business that supplies near 1,000 jobs. All small towns are not dying and the ones that are were mostly killed by government policies.
Sure those towns have had the infrastructure for years but those were before massive and state regulation. I worked with communities to help the receive grants and loans that were targeted on sewage systems. It is enormously expensive to build or maintain these systems.
Water and air regulations have also been imposed. Like small businesses they have difficulty in meeting the costs of this regulation (Entry Barriers) which are much easier for larger towns and businesses.