When Israel declared independence, that land was not governed by any state due to the withdrawal of the British Mandate. The Palestinians had previously been offered statehood through the 1947 UN Partition Plan, but had rejected it. They did not take steps to establish their own state in anticipation of the British withdrawal.

https://en.wikipedia.org/wiki/End_of_the_British_Mandate_for...

The majority of land purchases were made by the Jewish National Fund. Their aspiration to form a state was explicit and overt.

Sorry, you're saying there were and are no forced expulsions of Palestinians?

If I understand what's happened elsewhere correctly, then we have an example of this elsewhere at the world stage -- the separation of Kosovo from Serbia is in a large part due to land purchases from Albanians, who then vied for independence when their population grew enough.