Linked from
The 8 pages that link to Cartographic generalization, each with the reason it gives.
Map scaleRelated: As scale decreases, generalization controls which features remain visible.
World mapRelated: A world map must omit or simplify features that cannot be shown at global scale.
Google MapsRelated: Map labels and detail change with zoom level to keep the display readable.
Spatial dataRelated: Maps simplify spatial data, changing which details remain visible.
Map symbolRelated: Generalization determines which features symbols preserve, simplify, or omit.
Mark MonmonierRelated: Generalization makes clear why every map leaves out information.