The decline of rural regions and small towns is a global phenomenon, and the causes are many but boil down to two primary dynamics:
1. Cities and megalopolises (aggregations of cities, suburbs and exurbs) attract capital, infrastructure, markets and talent, and these are the engines of job creation. People move to cities to find jobs.
The San Francisco Bay Area megalopolis of roughly 8 million people in 9 counties and 101 cities offers an example of this dynamic. The region added over 400,000 new jobs since the 2008-09 Global Financial Crisis and over 1 million additional residents since the early 2000s.
In effect, the region absorbed an entire new city with 400,000 jobs and 1 million residents. Roads and public transport did not expand capacity, and housing construction lagged. As a result, traffic is horrific, homelessness endemic and housing costs are unaffordable to all but the favored few.