I might be misunderstanding the problem. If thats the case, ignore me. But are you switching classes along the way? An alchemist only makes alchemy collectables. A smithing collectable is still a smithing recipe, so you need to switch to smith first(and dont forget to make sure the collectable synthesis skill is active before you finish your craft). You can absolutely make collectables for any class you have higher then level 50 once the system is unlocked.