The majority of these Jews would bring needed skills with them. The Jews, as a people, tend to place a great deal of value on education.
The Palestinian Arabs who have spent the last 50 years sitting in "refugee" camps have few of the skills needed in a modern industrial society.
They would, instead, have to be supported, educated, and trained. All this takes a great deal of time and money, especially when the people you are trying to support, train, and educate have been taught to hate you since birth.
Lets not go into the whys and wherefores of the fleeing of the Palestinian Arabs in the first place. I'm not talking right or wrong here. I'm talking practicalities.
NO country could absorb that many basically untrained people and not feel a great economic impact and Isreal only has about 6,000,000 people in a very small geographic area.
Besides, Sharon didn't need to invite the Jews of the world to come and live in Israel. They already have the right to claim citizenship under Israeli law so his invitation was rhetorical grandstanding.

troll