Why can older city neighbourhoods decline when wealthier residents move to new housing tracts?

Older city neighborhoods often decline when wealthier residents move to new housing tracts due to the economic consequences of urban sprawl.

As wealthier residents relocate to newer developments, the tax base of the original city neighborhood erodes. Because municipal governments often prioritize subsidizing infrastructure and services for new construction, fewer financial resources remain available to maintain existing roads, utilities, and public services in older areas. Consequently, necessary repairs are frequently delayed or canceled, leading to a period of decay.1

This process is exacerbated by economic stratification, as Euclidean zoning practices in new areas often segregate housing by income, further separating different socioeconomic groups and draining the social and economic vitality from established urban centers.1