Yeah but people would buy Nvidia chips mainly for gaming, not (just) for CUDA, so basically the massive gaming clientele would finance expensive projects that don't yet make any money like CUDA. Meanwhile nobnody buys FPGAs for playing at home en-masse. There's no equivalent consumer market like gamers for the FPGA vendors, their sales are almost exclusively B-2-B.
FPGAs isn't something most people, even the hardcore tinkerers ned at home. Consumers into hardware tinkering are more than fine with what you can do with Raspberry PIs, ESP32s, STM32 boards.
IMO, this is a question about where AMD wants to be in the stack. They can sell hardware, they can license their IP, but they're going to be bent over a table selling software licenses that people don't want. A free HDL software suite can help you sell hardware and license IP, whereas an expensive one can cut you out of the FPGA/ASIC market entirely.