it costs at least a million USD to develop and fab an asic in any cost effective economy of scale...
A product like Xilinx EasyPath ($75000 NRE + lots of orders) would bring current FPGA upfront costs down quite a lot. What's needed for someone to gamble on such a venture is the belief that ASIC (or if you want to call EasyPath a hybrid FPGA/ASIC solution) miners would grab a significant share of those 7200 BTC per day. ($2/BTC is still $5.26M/year)
If the BTC price is going down to levels where it's just not profitable for GPU miners to mine due to electricity costs, that will indeed happen.
I looked at the Xilinx excel sheet yesterday. Did you?
edit: I haven't verified that $75000 is true for all FPGA revisions though, but the point stands. $5.26M/year is absolutely a market into which someone can spend hundreds of thousands if they believe they can capture a large portion of it.