We’re going around in circles. The reality is that “casing tension” as per the article you reference is actually a red herring. As is compound, profile, construction, bias ply, and tread. Not to mention aero… They are all factors, naturally, but avoid the fundamental issue which is that contact patch size, for the same weight, is only determined by tyre pressure. Not by rim width, nor by tyre size. The physics is very simple.
You are confusing the ability to run lower PSI’s in tyres, and in wider tyres particularly, with the fact that you can run them in all types of tyres. That said, the other important point is that, at the same pressures, wider tyres will show less rolling resistance (i.e. 28c<25c<23c) due to the different contact patch shape (shorter/wider, same area), but if you (as your article suggests) reduce the tyre pressures in your 28c or 30c tyres, then you will be increasing rolling resistance to the same of greater than your 23c tyre inflated correctly (i.e. 30c>28c>25c>23c). By decreasing pressure in your wider tyre, you are increasing the contact patch area so inevitably increasing rolling resistance. This may or may not matter depending on the rim profile and your usual speed.
As I stated, there are on-line resources showing this in real, controlled conditions (IIRC with Conti 5000’s).