With endgame-driven I assumed ppl will have alts, and as I remember my other mmo experience, on some of my alts I had no gathering skills, only crafting, thus creating demand for the low lvl materials, also equiping my alt with items from the market. Think about toons made for PVP only for example. There wont be any twink pvp in tor, but still someone (for example I will at a point) will level a toon only with pvp. Those will need gear as well apart from teh lvl 20-40-50 pvp gear.
I cant recall any of my mmo characters who actualy get crafting for their own leveling gear needs. But that is just me and only one opinion out of thousands, and what fits me may not fit others.