Yes, too much for a person to invest and make the ASICs worthless after it. But for a gov which does not like cryptocoins it´s nothing.
Although, a collaboration of people with a sizable amount of money could do that. As far-fetched as it sounds, the group of people who manage to first create a efficient hashing ASIC with 20nm half-nodes (the lithography hasn't been done yet, but it's the next expected step), beat everyone to the punch, and create it successfully in the infancy of this lithographic geometry could do some significant damage. The geometry could be fine-tuned by 2015, industrialized by 2016, and working tapeout by late 2016.
Of course we're talking about millions of dollars, and for a new geometry, it'd be classified as top-tier (at places like TSMC, GlobalFoundries, Renasas, and ON, their top tier BUs are at the minimum $100M). So the biggest issue is how to either (a) recoup the money for a BU that decides to do this or (b) find a bunch of people to "waste" that much money.
tl;dr: Could happen by 2016, but someone would have to be willing to spend 10s, if not 100s of millions of dollars.
