I'd say that this is an argument that you should vote for systems that treat people fairly regardless of class. Even if you have no chance of becoming a millionaire or billionaire, it seems to me you should still try to treat such people fairly - according to sound principles that you would be willing to apply to yourself if you were in their position.

Likewise for the very poor. I hope to never be very poor, but I still wouldn't vote for systems that mistreat or exploit them. This is not because I'm trying to protect myself in the circumstances that I become destitute, but because I think morality requires the consistent application of principles to people regardless of their economic wealth.