The Pallies alternately claim descent from both the Canaanites and the Philistines, but either way they aren't the owners of the land (even if their claims were true, which they're most assuredly NOT). All peoples who inhabit the land of Israel are there at G-d's sufferance. G-d, in his infinite wisdom, has decided that the Jews as a people shall be the owners of the land, as long as the Jews obey His laws (and plenty of woe follows not doing so). The Canaanites were deemed unworthy of holding onto the land over 3,000 years ago, and no one since then (until the Arabs wanted the land) has claimed to be a Canaanite. In fact, if the Arabs truly believe in their own Koran, then they MUST believe in the Hebrew Bible, and therefore must believe that only the Jews can own The Land. Regarding the Philistines, they were known throughout the Eastern Mediterranean as "the Sea People," who were invaders all over the place. No one knows with any degree of precision what their origin was, but they are thought to have been ethnically from in or near what is now known as Greece. The Philistines were wiped out as a nation long before another set of Greeks (led by Alexander) took over the Holy Land. As with the Canaanites, no one since then (until the Arabs wanted the land) has claimed to be a Philistine.
Oh, and as to why what is now Israel was called "Palestine," we have the Romans to thank for that - after the Bar Kockba revolt ended in about 135 CE, the Romans banished Jews from the land and called it "Philistia" after the historical enemy of the Jews. Before the Arabs, there was precisely one people that called themselves "Palestinians," none other than the Jews of pre-1948 Israel. I have a copy of the main newspaper of the time announcing the independence of Israel - that paper was the Jewish-controlled "Palestine Post" (now known as the "Jerusalem Post").
The simple fact is that the people who now call themselves "Palestinians" are no such thing. They are virtually all descendants of Arabs who left surrounding countries in the late 1800's and early 1900's to move to a land where there was food and jobs, much as most of the black population of South Africa is descended from those who came there in roughly the same time frame from surrounding countries, also for the same reason.