“I shall not want.” is sometimes rendered, “I shall not lack” or “I shall not be in want.” It’s an incredible promise for those who are his sheep.
But it doesn’t mean we have everything thing we want; it does, however, mean that our Shepherd will supply us with everything we need. He has the supply, and he gives from his supply as needed. We can relax, stop worrying and trust. The Good Shepherd will provide.
Of course, you have to be following the Shepherd to get in on the provision. Those who stray are on their own.