Don't reuse the same address for other transactions, so you're much safer when using quantum computers. Nothing is truly secure for asset storage if someone isn't careful. Even if a wallet is sophisticated, if it's not well-secured, it can sometimes be hacked. As far as I know, quantum computers will only record the private key and the public key, so the solution is not to use the same address for multiple transactions. There's been extensive discussion on forums about asset security, and you might want to research the appropriate steps to better understand the best practices.
The technology is there, but usually the error are in the human factor field, you are right.
And as it was outlined - there are already articles and threads regarding what can be done about it, which is truly awesome.