That's because they had the power to go to war to enforce their contracts. Etherium holders do not have such power, so ultimately, relies on the country's laws to enforce the smart contract.
Game theory is the more fundamental thing that power ultimately derives from. From the paper I linked:
"Focal arbitration power is power to redefine property rights, which of course may be
profitable for the focal arbitrator himself. But a society's generally understood rules for
recognizing leaders can impose constraints what a leader must do if he wants to retain his
generally recognized position of authority."
"Focal arbitration power is power to redefine property rights, which of course may be profitable for the focal arbitrator himself. But a society's generally understood rules for recognizing leaders can impose constraints what a leader must do if he wants to retain his generally recognized position of authority."