The material is only a part of what makes a good interior, there are many other things that determine the quality, either subjectively or objectively. The design is the major part, how it's laid out, where the buttons are, how they feel to use, where the dials sit, how clear they are to read, how focused on the driver it is. Audi has historically lead the way on that front and their latest cars I think are a return to form, though for me the jury is out on the fully digital displays. Also the touch and feel is important, soft textures over hard, matt plastics over gloss plastics, high quality stitching to leather, mixtures of textures on doors and dashboards. But for me the most important is how well it all fits together, is is tight and rattle free and are the touchy feely bits nice to use. Little things like damping of hand grips, control surfaces, cupboards and storage all add to that and again have been something Audi has done, mostly, brilliantly and why the car I posted above is such a let down as it does most of this stuff badly.
To my point above the components that go to make up something are only part of the equation and are not the determining factor of what looks and works the best. If that were the case then all cars would feel the same and that is not the case, far from it.