The reason why they are so special is becuase of its rarity. Thats why its an amazing feeling to finally get one, instead of crafting one like a noob. You get a good feeling, and feel accomplosihed for doing so. Thats why they are precious and a unique item. You wouldn't make wither stars, and wither skulls craft-able would you? If they were craftable, you could make as many as you want and it defeats the entire purpose of them being so rare. Idk about you, but i would rather find one with hard work.
Go out, find a trident, and EARN IT, like a real minecraft pro. Crafting tridents would be an interesting feature, but a recipe for them shouldnt exist.