[stromgo]

The qualifier "dwarf" doesn't mean that the celestial body is too small to be considered a planet, it means that it hasn't cleared the neighborhood around its orbit. (Blame the IAU if you find this counterintuitive). This means that your conclusion is wrong: the asteroid belt actually has enough mass to be a planet.

[stardek]

Other than not having enough mass, what would cause a celestial body to not clear its orbit? The only other factor that occurs to me is time, is there anything else? If not, does that mean Ceres may eventually become a planet?