Maybe, but if a state actor has achieved this ability, I doubt they would make its existence public knowledge by stealing a few billion US$ in btc. That's chump change compared to the value of being able to surreptitiously crack the cryptographically secure messages of everybody in the world.

Note I'm not saying that I actually think someone has achieved this, I just don't think "no one is stealing btc" is a good non-existence test.

Pretty much, it's not just bitcoin either, basically every cryptocurrency wallet is based on elliptical curve cryptography and any that have been used publicly are vulnerable to anyone on Earth having enough coherent qubits at their disposal to crunch the numbers in order to steal it.