Well, that money is buying weaponry created by US companies for the most part. My point is the federal government budget over that same time period is in the many trillions, and $300B is just a fraction of a percent of that.
in the past few years, OpenAI and other companies like it have received relatively the same amount of money the USA has spent on weapons for the past 70 years it seems.
so relative to that, yes, it is cheap...