I don’t care about what happens after the data is written in the blockchain. I care that accurate data goes in in the first place. that part blockchain cannot solve. And if inaccurate data does make it in, I want it corrected. So I’d have to trust someone to make those changes.

That’s unsolvable in general besides through consensus algorithms (which blockchain can facilitate). I’m not really sure what the example here is in the analogy we’ve been using - an auto manufacturer sells a car to someone that’s a different model than they wanted? They could refuse purchase.

Blockchain adds authenticity through proof of when it occurred, which is not available through signature chains.