The analysis is not always done sufficiently (or without bias) but that's the idea.
I've never seen a politician mention this kind of (we spend x for y returns) discussion or a doc on it holistically.
It's obvious to most people to invest money can give you more in return but that's not really discussed except peicemeal for one program at a time.
Social programs are popular with voters (well, the ones who benefit from them without paying sticker price), no one ever wants to take a step backwards in lifestyle (especially government employees), and there’s an unwavering belief that any amount of spending is “fine”, all we need are those damned rich people to pay their fair share.