For one thing, the social contract among the states was already changed in the 1860s. We're no longer some loose confederation of independent states. The Feds are in charge, whether you like it or not, and the states are effectively administrative divisions, whether you like it or not. We literally fought a war about this and the "states' rights" people lost.

For another, we're not bound to contracts between people who are long dead.

For another, the constitution (little c, not the actual document) is not a literal contract. That's a methaphor.

Finally: Why do you, as a person, want a system where land can vote? Or are you a parcel of land pretending to be a person?