When people have a choice they tend to move to improve their lives. This
is called the free choice model. It doesn't work very well when the
people who are being moved have little or no choice. Forced relocation
is occurring all over the globe. To say that people move from rural to
urban or from crowded to spacious is really simplifying the situation.
Both situations occur but not with the same groups of people. On Earth,
workers are migrating from rural areas to urban areas in search of work
to feed themselves and their families. On Earth, after WW2 in the US,
many people moved from the cities to the suburbs. This caused urban
decay. Now urban areas are being backfilled by the single and relativly
wealthy, displacing the urban poor who lived there earlier. The point is
that many factors influence populations. If you want to explain why
there are planets with 242 people on them and next door planets with 242
BILLION people you will have to try harder...
not intending to flame,
Steven Gott