The ebeam write time for imprint masks is virtually irrelevant. The ebeam written masks will be used for masters to make very cheap (~$5K) mask replicas using a specially designed imprint mask replication tool. A master can produce thousands and thousands of replicas, thus amortizing the master cost to virtually zero.
I'd imagine if EUV tools were available in 2011-2012, some companies would still be able to skip immersion and double patterning entirely, catching up to those who bought EUV, and immersion, and double patterning. The dragging out of 193 nm technology has enabled leaders to keep their lead.
In the 2012-3 timeframe, all the 193 nm immersion customers are either using double patterning to get ahead or staying behind with single patterning at 4x nm. If a sudden reduction of litho cost occurred in 2014-5, those who stayed behind and avoided the massive costs of double patterning would benefit more, somewhat unfairly.
If memory serves me correctly, the master imprint mask is written with an e-beam writer, but the replica masks are produced using the same nanoimprint process used for IC production -- the master mask imprints the replica masks. So e-beam write times shouldn't be a major factor.
Yes, it is happening in China where all the big firms are pumping research money. They make so much abroad and hate to send back to US to avoid paying taxes. Suddenly they have to spend that money offshore. That is where it is happening
even with NA = 1.3, interferometric tools give you ~ 45 nm pitch with 193 nm light. Plus double patterning you get to 22 nm. That's a one generation tool. Let alone the lack of maturity and versatility of the interferometric tools.