[kkylin]

At least in my area of mathematics, journals still do some copy-editing, mostly to conform to journal style and fix obvious grammar / spelling mistakes.

Journals do sometimes advertise, and that can be expensive. It's also one way to get a large impact factor etc.

About university presses: I don't know how they're funded internally (despite being faculty at a university), but I would not be surprised if they have to fund themselves. It's hard to see student tuition dollars supporting a university press, nor can research dollars flow that way. It's possible some public funds (at state universities, at least) can be used to support university presses, I guess.