I enjoyed the history on the fabric, but as you know, we have to agree to disagree with respect to its performance.
For one, it is not a true waterproof material. It is a softeshell fabric, and I have no idea why people keep comparing it to laminate based hardshells like GoreTex, which are actually waterproof. Ventile is much closer to modern softshells like Pertex.
The "strength" of the fabric comes from its thickness. For the same thickness, a Ventile jacket is not any stronger than many of the other modern fabrics on the market. It is of course stronger when made extremely thick, something needed for even relative waterproofness in heavy rain.
Due to the properties of the fabric, Ventile jackets end up being very heavy when compared to modern ones, are exponentially heavier when wet because instead of repelling water, they absorb it, and once wet, takes huge amounts of time to dry out, not to mention that they are not at all breathable when wet.
I'm not sure who "those in the know" are, but they seem to be a tiny, tiny minority in the outdoor community, as most of us wouldn't use Ventile clothing even if we got paid for it.
People like what they like for numerous reasons, and that's fine. However, the appeal tends to diminish greatly for anyone who's had to carry a wet Ventile jacket for several days through the woods.