You've been kind enough to make a testable prediction here! Let me make it a little more concrete. Currently Bitcoin block 700000 has the hash 0000000000000000000590fc0f3eba193a278534220b2b37e9849e1a770ca959, I'm very confident that 5 years from now it will have the same hash. What do you think is the chance that history will have been rewritten?