It is just how much worse it is that "real" science. In biology or physics you need to spend loads of money and do real science before you even get the data. Economists just need to read it off the computers, or account books back in the day. Whether these people work for the government and had access to tax records, work for the bank and had access to private finances, or in this day and age anyone with access to the internet and the computing resources needed to process the online add marketplace. I do not see why there is not more hard data plus good maths coming up with statements about the world of similar confidence to what we can say about deep space, the far past and the human body.