I have worked at an FPGA company, but on soft-IP, so I have some expertise but I wouldn't consider myself an expert, but I've certainly talked to them. What I o

I have worked at an FPGA company, but on soft-IP, so I have some expertise but I wouldn't consider myself an expert, but I've certainly talked to them. What I observed is that whilst there technically is a bit pattern being programmed to hardware, the rules surrounding what combination of bits is incredibly complex. The simplest example of this is that you could programme two registers, one to drive a net low, the other to drive a net high and just basically screw up your chip. The rules that prevent that aren't a set of last minute "sign-off the image" type rules. Thhey're embedded into every part of the compiler. There were game changing hardware resources that genuinely were going to be hidden from customers because we didn't have the software resources to actually expose them in a safe manner (honestly, it's really very complex). Ok, so that's the technical reasoning. On the business side, FPGA companies (like basically every ASIC company today) produce 1 design and disable a bunch of stuff for market segmentation. VU7P? Well that's physically the same as the VU5P but the software limits what you can compile on to it. So to enable open source interfaces they'd need to add an entire layer of DRM ontop of the current solutions. You can argue about the ethics, but it is what it is. Also, marketing drove Altera and Xilinx. Don't get any ideas that these were silicon valley engineer led start ups. It was a marketing game, you see that in their leadership and I'd argue you saw it in their share price growth too.