If we were to remedy this issue, here's how: re-validate every transaction in evvery block in the entire block chain, EVERY time someone loads up their Bitcoin network.
Well, no, Carlton. I would advocate that every transaction be validated at least once by each client. Upon initial download.
I would be more than happy to trust that data on local storage had not been meddled with. Heck, we've got the world's best cryptographers, right? We could secure data-at-rest with some sort of hash or something to ensure that nobody de-installed the drive, modified the data, and reinstalled it since the last time we ran the node.
If that were a worry.
I am just pointing out that -- with the current Core implementation -- we do indeed need to trust in the goodness of others. For validation of older transactions. We are decidedly not operating in a trustless manner. I am heartened to learn that -- on this point at least -- you agree.