Unless you actually spend time either farming or doing 'overland' questing, where you harvest anything you see, you will definitely run out. I did stop doing the alchemy writs for a long while because
I've been playing about as long as you and never stopped for the 10-12 months you did by your post and would not ever consider myself to "have enough" alchemy mats even if I have 700+ of everything be
ZoS' previous statements have said there there "Isn't anything 'rare'" in alchemy, which is why there is no hireling. You can buy waxed apothocary parcels in IC for 500 TelVar each, which is actually