If you really want to know about Philistine origins, come to Cyprus. Not that the Philistines originated here, but here the evidence seems clearest.
The Philistines were one of a group of related peoples called the Sea Peoples, who emerged seemingly out of nowhere at the end of the 13th century B.C. As we know from the Bible, they ultimately settled in southern Canaan and dominated the surrounding area until subdued by King David in the early 10th century B.C.
To understand the origins of the Philistines, we must understand the state of the world at the time of their emergence in the late 13th century. That world was coming apart at the seams.