I think it can be forgotten writers are not robots. Ideas need to develop and grow. That needs time. I don't think it can be rushed either. I've found some stories do simply take longer to write than others. This can be because I haven't outlined properly (again you need time to think out your outline). Sometimes the outline isn't an issue but the idea just needs thinking out for that big longer.
So whatever way you can develop your thinking time it pays to do so as I think it will improve your work longer term. Thinking time is part of the creative process. It shouldn't be seen as an annoying irritant. Stories need working on and thinking time is part of that work.