Pretty soon, as time goes by, everyone and his dog will be a r50 crafter in every or almost every craft. No one will need anyone else for any crafting need.
However a good way to prevent this is to have craft 'specializations'. A one time choice of one or two crafts to specialize in, increasing stats, success, and allowing synthesis of 'specialist only' materials, equipment, and goods.
Everyone will still be able to do every craft, but have those one or two crafts they can make everything in, including advanced items.
Ex: A specialized culinarian would be able to make foods that give higher stats, and more than 2 stats (the current food amount)