We don't "let" others add that value. We just don't compete effectively. If someone else is going to buy our raw materials and turn out finished products cheaper than we will, someone else is likely to end up with the contracts.
Whether Canadians can compete effectively and efficiently depends on personal expectations, and how the governments regulate enterprises.
Reading and watching commentary across the years, it is clear that too many people spend too much time wondering why someone just doesn't "do something". Do they even understand the rules of engagement? If they understand, are they prepared to make changes that will make Canadian enterprises more competitive? I can guess that the answer to almost every proposal will be "oh, we can't change that".