I'd be really surprised if someone dumped them - they'd only hurt themselves in the short term. Given the discussions on the google dev group, this quotation from yesterday seems apropos:
Note that such a death spiral and the incentives for a soft fork are possible prior to quantum attacks on Bitcoin. Merely the threat of quantum attacks and the widespread belief that Bitcoin will not freeze unspendable coins and thereby inflate the supply of spendable bitcoin.
In short, while I don't think it has anything to do with quantum, the fear that something similar could happen in 5, 10, 20, 30 years with huge uncertainty is the issue.