I'm sure this idea has probably already been brought up and shot down so please forgive my noob idea. Would it be possible archive the blockchain every few years? By this I mean take a snap shot of all wallet balances removing the transaction history and greatly compressing the data, this would become the starting point of transaction verification for the next few years and the archive (which would contain the full transaction history over the past few years) could be distributed by archive nodes. The archive nodes would not be necessary to validate new transactions so someone could run a "full" node without the archive. You wouldn't need as many archive nodes as full nodes and even if the archives become several TB in size there would still be people willing to provide the storage necessary to secure bitcoin.