If you want to proof you didn't temper with the historic data, publish a daily hash in some newspapers.
Actually I would say that that is exactly what blockchain does, except as a protocol and relying on a network rather than a newspaper. Actually I might use this to explain blockchain to people on a base level.
So you're suggesting that publishing a hash in a newspaper every day is a better solution than a digital ledger? This is peak buttcoiner logic. That actually used to be done [1], because Blockchain are valuable, but not anymore because digital versions are more scalable, efficient, reliable, global, trustless etc. Etc.