A small increment on the Luhn formula of 1954
A Checksum is as good an idea now, as it was when the Luhn formula was introduced in the 1950's to prevent transposition errors by fat fingers: It was a key-enabler for the use of electronic computers but was simple enough for mechanical terminals to validate at the point of entry.
We quickly realised that a checksum could be applied to records and blocks to prevent bit-flipping corruption in core memory, tape and disk.. apologies for the primary-school explanation, but we need to be clear, exactly how old and simple the idea really is. The blockchain innovation is to  store every transaction forever (tiny compared to a “cat photo”),  add the checksum to the next block in the chain (to prevent change),  duplicate the chain in loads of places (like RAID-10 + DR).
What is not particularly “innovative” is generating millions of random keys to find one that happens to hash to the same checksum as the whole block.. neat for Iceland where electricity is cheap, but far away from where anybody actually lives.
When all the bitcoins have been mined, the only incentive to maintain it will be with the handful of mega-miners that burn through more electricity hashing than global supply was 50 years ago.. what we in this old-school world call “a central bank”.