Bitcoin nodes only need to work with the state of existing spendable coins. The need to track previously used stuff in some other systems to prevent transactio

Bitcoin nodes only need to work with the state of existing spendable coins. The need to track previously used stuff in some other systems to prevent transaction replay is a design flaw that Bitcoin avoided. The vast majority of the blockchain data is digital signatures which you don't need anymore once you've validated them (except to help other people sync up).