[kinghajj]

That's not really a problem. Addresses aren't the entire ECDSA public key, but a hash digest of it. The entire public key is only revealed once a transaction is made from an address to another. So an address that has only received coins, but never sent any, is entirely immune from QC. (This, by the way, is why you're never supposed to reuse addresses, since once you move coins from an address once, it's possible for someone offline to try and break the key.)

[tromp]

It is a real problem. Millions of BTC are locked in addresses with known public key, due to either the formerly popular Pay-to-Public-Key script, or the ever popular practice of addresses re-use that you also mentioned.