It's mainly a question of volume. ASICs have a big economy of scale, so the cost-per-chip goes down considerably once you go over a certain number of chips. Plu

It's mainly a question of volume. ASICs have a big economy of scale, so the cost-per-chip goes down considerably once you go over a certain number of chips. Plus, there's all the NRE costs of an ASIC design over an FPGA design. Google probably figured they could use enough chips to make the cost of manufacturing ASICs worthwhile. I don't think FPGAs are going to be beat out by ASICs for low volume applications anytime soon.