In many cases the surrounding Arab countries told the 700k to flee the land as they would defeat Israel and would welcome them back once the victory was secured. It didn't work out that way and the same Arab countries didn't want to accept these people in their land.Actually incorrect in that there were plenty of Jewish attacks on Arabs well before 48. As well as vice versa.
In addition the first Palesinian war was caused by the destruction of Palestinian villages and the subsequent fleeing of 700,000 people.
Not sure you quite get how much Palestinian land and property was sequestered during this period.