Since when is Intel fabless? Even if you have your own manufacturing, prototyping still costs you a lot of money. You still have to pay the people, materials and machine time. You can only save the profit margin since it's internal cost. And it might not be that bad. They stand to make a lot more on volume manufacture of a finished design. They want you to succeed. This shouldn't be a problem for companies that are already established (they have the capital and confidence to commit to wafer volumes). Also, you don't need that many FPGAs for prototyping. And I'm not sure how big a role they play in CPU, GPU or mobile SoC development. Those chips are big and cutting edge. Also, their design is not naturally FPGA friendly. Your first line of defense against errors is software and companies like AMD can afford the best there is (which is eye-wateringly expensive). It would be interesting to know what kind of success rate someone like Intel has on first pass and how they achieve it.