Well the difference is that Israel has invested in desalination at a widespread level. They've been able to irrigate the desert and turn inhospitable land into arable farmland with that investment.
While 10,000 visas may seem like a lot, it actually doesn't go all that far for the sort of crops that must be picked by hand.
Since 2004 Israel has respected every inch of the 1967 borders in Gaza. The disengagement was designed to prove to the Israeli people that a pull back to the 1967 borders on their part would lead to peace.