384Mhash for ~$2100.
10 months to break even at 6000 difficulty $.10 power
25+ to break even at 12k diff and $.10 power.
(according to Coin Warz calculator)

I'm sure your numbers are right. But I think you are assuming there will be no virtuous cycle provided by a more secure blockchain. A Chinese company committed time and people and money to design, tapeout, manufacture, characterize, and bring into production an IC that is dedicated to mining X11 secured blockchains. This is capital intensive work. This is not rolleyes. This is a vote of confidence in the future of DASH.
I agree, and it was always assumed this would come one day. The best thing is, though, that miners won't be making any decisions on which transactions are valid when Evolution launches. This will be done by Masternode Quorums, thus no fear of 50% attacks. Or any such attacks from miners anymore. And just note, there have never been miners who have attempted such an attack on Bitcoin, though there have been opportunities. So I'm not sure how much a danger that poses. Still, this vulnerability will be no more in Evolution.