Quality does matter a great deal. But is there an end to how much you should deliver? Chasing quality has a cost in time and money. You are using someone else’s time and you are not able to fulfill other opportunities that would be revenue generating.
I think artists struggle with the boundaries. It’s not necessarily an issue of how much to give but rather when to stop.
The content may be good enough lest you miss a publishing deadline. The artwork could use more refinements but the client has not paid for it.
I guess the best question to be asking when dealing in project work is, “Who’s expectations are you meeting? Yours or the client’s?”
Part of being a great artist is that quality is the focus.
But, as Steve Jobs famously said, “Real artists ship.”