Quantum computers are not common, so it's too early to talk about anything. And besides, this technology has not yet been finalized
The question is important for the future of Bitcoin.
Imagine a BTC price > $1,000,000 and more than 1,000,000 'shalecoins', coins with no owner
https://bitcointalk.org/index.php?topic=5134441.0 would become active.
The value of these coins would be > $1,000,000,000,000
How can that work?