If the Spanish American war never happened the Philippines would have remained under Spanish rule until WW2, when Japan would have took them. If Japan was never defeated, millions of Filipinos would have been killed and it wouldn't be very rich (at least not for the average Filipino). If the Japanese were defeated and the Philippines became independent it probably wouldn't be any better off than it is now. Now an alternate scenario being if America drove Spain out and then demanded the Philippines be independent, they would probably be an ally of America (similar to Cuba) and then be invaded by Japan in WW2 (same result as above). A variation of this being the Philippines becomes independent and pursues and independent foreign policy (no American relations), then they may prosper some (not much as they wouldn't have enough educated people or experience to build their country into prosperity) but would again, be invaded by Japan in WW2 (unless they ally with them like Thailand). Either way, after the war they would prosper but not significantly more than in the real timeline.