I understand where you're coming from, but the empirical history of America (at least) brings up two problems. The first is that the definition of race/ethnicity tends to shift based on what's politically expedient for the powerful: consider whether Irish people, Eastern Europeans, Arabs, and Jews count as "white" at various points across American history. Race just isn't a solid enough concept to be a reliable way to ensure a share of power for anyone who doesn't already have a unrelated strong grasp of power.

The second is that in practice this just causes the weak to identify with and have solidarity with the strong, which isn't the direction you want. There's a lot history of public policy in America that's been targeted at getting lower-class "white" people (for whatever the current definition of "white" is) to believe that their self-interest is more aligned with the success of the white race than with the success of the lower class regardless of race. You can see this clearly in the history of things like Bacon's Rebellion, and the establishment of slavery in the US as a racial-superiority thing as a way to avoid a combined revolt by white indentured servants and black slaves against the upper class. But I think you can see the same thing happening in the present day.