Fireman, I understand what you are saying. But, in my opinion, you have mingled two totally different types of food prep using smoke. You mention smoked salmon, jerky, cold smoked cheese, and that old fashioned smokehouses weren't sealed. This is true, as they were intended to smoke food as a preservative measure, i.e. smoked salmon. Salmon was smoked to preserve it so it could be stored and eaten at a later date. Same thing for jerky. It is used to preserve beef so that it can be stored without refrigeration.
The other side of the coin is using smoke as part of a cooking process, such as on a brisket. Here you are not simply trying to preserve the cut, which you really couldn't do due to the thickness of the cut itself. You are actually cooking the cut, using low heat, and long cooking times. The smoke is used to impart flavor. For example, I do brisket at 225 for 10 to 12 hours, and add chips for smoke for the first 5 hours or so. I could cook the same brisket in the oven for the same time at 225, and it would be done, but without the smoke flavor. In today's world, the term "smoking" has come to be another way of saying bar-b-queuing.