You’re right that it’s large in an absolute sense, but any sector of the US economy is going to be large in an absolute sense. It’s not a very meaningful statement. Using percentages allows comparison to other items, which for some purposes gives a more useful sense of size. For instance, based on your numbers, AI expenditure is about 1/3 the total military expenditure. I tend to agree that this is less than I expected, and generally makes me feel a bit better about the (imo excessive) hype.