1) Israel is an important intelligence ally, military foothold in the region, and both source and buyer of military research and applications. Anything that disrupts this arrangement risks hundreds of billions of dollars and the perceived national security interests of multiple countries.
2) Reparations to Palestinians would not only be extremely expensive, it would also raise questions of potential reparations to other victims of Western imperialism and apartheid, including to Native Americans, Native Austronesians, and much of the African continent and diaspora.
3) Securing the existence of Israel as an ethnostate drives political support from Western Zionists and Evangelical Christians. Even a change to a more stable, secular, multi-ethnic Israel would see not only the revocation of support but also active retaliation that, at best, would get your a chapter in a Profiles in Courage reboot.