I think cryptocurrency is a fundamentally new invention because despite many people's efforts, nobody was able to achieve decentralized digital currency before Bitcoin.

Just the fact that a blockchain doesn't scale in an obviously good way is probably part of what confused people into not inventing it sooner. Surely if total storage requirement increases without bound, it can't possibly run forever! Well, humanity won't run forever either. It just has to last long enough to be useful while it exists.