The palestinians were largely nomadic people and did not seem to have much interest in establishing governments. They wanted to live on the land and be free, and ffrankly it worked great for them for quite a while.
The palestinian government only needed to organize much later in history once they were already under attack.
Its also irrelevant, what matters is who has citizenship over the land and a say in how its run (people born there).. whether they choose to organize into a government to do so or not means very little.