[rndphs]

I think it's more that if someone builds a sufficiently large quantum computer for other purposes then it would also break bitcoin as a side effect.

[bubblecheck]

Indeed, a viable QC that can break existing widespread asymmetric crypto is worth far more than the total mkt cap of all "crypto" at their combined peak.

Most likely this will be wielded by USA or China in secret (if not being done already)