I think one could argue that being able to make chips in the US is a national security concern. Leaving all the politics about who and why out of it, that kind of budget isn't out of the realm of possibility from that angle. Submarines, satellites, and aircraft cost a lot too.

Btw, I'm taking your word for it that it would require that amount of funding. I've wondered why Intel can't dig themselves out of the hole by adapting to the market. From my naive point of view, it sure seems like someone could make matrix multiply / relu chips a lot cheaper than Nvidia prices. I don't think people care much it being CUDA so long as they've got something to wrap up in Tensorflow or PyTorch or whatever.