Personally I enjoy the process of optimising my time by crafting one set of things while gathering resources for the next, I see that as a fun part of progressing through the game.
As some of you have pointed out the economy is at the heart of this, with decisions being made over whether to crafting something yourself or buy it being interesting at all levels. I would say that applies to basic tools as well as more advanced things.
There are a couple of upcoming mechanics which will feed into this: Firstly progression will add skills that reduce crafting time. Secondly there are Engines, which are add-ons to machines which increase the power of the machine. Some recipes will need a certain amount of power to be able to be crafted, but also using a machine with high power will make recipes craft faster. The idea behind these mechanics is to allow the specialised crafter to have advantages in time (and therefore fuel) over someone who has specialised in other areas, so they can produce more items quicker and cheaper, and make money selling them.