Fiction side here: this is actually a question in flux. It used to be that you could expect serious developmental edits from an editor and also your agent on to

Fiction side here: this is actually a question in flux. It used to be that you could expect serious developmental edits from an editor and also your agent on top of multiple copy editing rounds. However the recent cuts in labor has limited how much editors can read or acquire, which then affects how many books agents can represent and then forcibly raises the bar for the quality of submitted manuscripts. It’s like the post doc problem (where phd graduates are pressured to take more and more extreme measures to be qualified for a professorship position and therefore do significant work for exceptionally little or no gain).