It still leaves the possibility that the trusted third party operating that database (or Amazon) could modify the data. Blockchain would allow the same thing where that actor is malicious.

Though the real world problems we're solving rarely lack a trusted third party. And even when they do, a public log a la certificate transparency logs seems to solve the issue about as well in my eyes.

What allows that is multiple copies maintained by separate entities. If you have that, you don’t need a blockchain. If you don’t, a blockchain is just distracting from the problem.