You missed the most salient point about TrusJoist-type floor framing in last week's column.
Dimensional lumber varies in thickness by a half inch or more throughout a typical floor.
Even if a diligent carpenter spent time ripping all the lumber to the exact same size and then perfectly matched all the crowns, by the following week the lumber would change due to differences in grain, moisture content and species. So you would again have an uneven, unstable floor. If you glued and screwed every joist you would have a reasonably solid floor, but it would not be flat and, again, no one is going to go to that kind of trouble. Engineered lumber is extremely consistent. And, because it has no grain, it is also extremely stable.