Why is Israel leaving the Gaza strip? Well one reason may be because it is one of the poorest places on earth. The CIA tells us unemployment is 50% (ranked 185 in the world) and GDP per capita is $600 (ranked 229)

Incidentally, I must commend the CIA factbook in that when talking of the Israeli population they say:

Population:6,199,008
note: includes about 187,000 Israeli settlers in the West Bank, about 20,000 in the Israeli-occupied Golan Heights, more than 5,000 in the Gaza Strip, and fewer than 177,000 in East Jerusalem (July 2004 est.)

Mnost commentators ignore the Jerusalem settlers.